Apart from the following exempted countries Angola, Antigua, Bahamas, Barbados, Belize, Comoros, Cyprus, Eritrea, Fiji, Gambia, Grenada, Jamaica, Kenya, Lesotho, Malawi, Mauritius, Madagascar, Malta, Rwanda, Sierra Leone, Singapore Solomon islands, St. Vincent & The Grenadines, Swaziland, Sychelles, Tanzania, Tonga, Vanuatu, Zambia and Zimbabwe. The rest are required to obtain visas. The visas fee are: Student visa-US$20 (I stated under occupation in the immigration form that I'm a student and the officer verified it by showing him the ISIC card, international student card), Single entry-US$30 (the single entry visa is valid if you travel to Kenya or Tanzania and then return to Uganda). Transit visa-US$15, Multiple entry-US$80 (6 months) and Multiple entry-US$160 (1 year). The visas can be obtained from Uganda's Diplomatic Missions and Consulars abroad (that includes Kenya and Tanzania as well). Alternatively from the immigration's offices at Entebbe Airport and any other land border on arrival.
Getting to Uganda
If you come by plane you arrive to Enttebe airport, mostly you can get from others destinations in Africa and you have also flights from London. To Uganda you can arrive by road from Kenya the easiest way, you have a bus twice a day which connect Nairobi and Kampala, of course you can do the way by the matatus and cross the border by yourself. You can go with matatus to Tanzania and then cross the border by yourself, maybe in the future will be a new ferry to Tanzania and it'll be easier to go there. You have also a bus to Kigali in Rwanda another place to see the mountain gorillas, which is cheaper than Uganda especially if you got a student card (you need a visa to Rwanda, which you can obtain in Kampala
Where to go
one of the nicest country in Africa, this country is much less touristic than her neighbour Kenya so the locals are much more friendly, I felt the most safe to walk in the streets even at night than in all Africa. Uganda is the place where you can see the source of the Nile (the longest river), The source of the Nile you can see in Jinja, this place isn't a must seen place, but it's a nice place. Jinja is only about 1 drive from Kampala, so you can do this as a day trip. The gorillas can be seen in 2 parks in the west of the country it's almost mission impossible to get a permission in Kampala to see them, but if you go to the park you can always find (if you wait a few days) a free place to go. It's one of the best things I did in Africa and it's amazing to see how the gorillas live, but it's very very expensive you pay about 150 US$ to see the gorillas for 1 hour, bring some sensitive films (400 ASA and higher) to your camera since the light inside the forest isn't sufficient. The mountains Gorillas are lived in the area near the borders of Uganda, Rwanda and Congo (Zaire) and you can see them in all those countries. You always should ask others travelers where it's the best to watch the Gorillas, because they can move from one region to another. To cross the border to Congo (Zaire) you get a temporary visa only to go to see the Gorillas and you pay 50 US$. Also you should decide according to the political situation . It may be dangerous to see them in Rwanda or Zaire. A very nice forest is Kibale forest near Fort-Portal where you can see the Chimpanzees if you got a luck. Another thing that you can do in this part of the country is to climb on the Rwenzori range of mountains. The top of the mountains are covered with snow 365 days a year. The around Rwenzori hike costs 480US$ and least 7 days/6 nights, and you pay extra if you fail to complete the route in 7 days. This price is included 1 guide, 2 porters for your private stuff and accomadation, they let each porter carry only 12kg and you allow to carry with you only small bag. The full tariffs can be found in the UWA website. The hike can be booked either from the start point near Kasese or UWA office in Kampala, I did the hike in October, which is the beginning of the rainy season, the area on altitude of above 3000m was very boggy and made it very difficult task to walk. I took as they advised rubber boots and it helped much when we walked in the bogs. The highest peak is Helena which is 5199m above sea level, in order to reach this peak you must have the appropriate gear to walk on ice, which is axe and crampons that you can hire at the beginning of the route. They wouldn't tell you, but it's possible to do also a 1 or 2 days hiking, but you will see only the low areas. Another place that I visited is the Sesse islands this peaceful and untouched islands are inside Victoria lake, you can take a fisher boat from Kisini (1/2 hour from Kampala) to the islands, which take the fish in the morning to the land and return with groceries to the islands in the evening, the journey takes a few hours I started at about 3 PM and arrived at 10 PM, we stopped for about a hour on a small fisher island and we ate fish meal made by the locals. I stayed on the biggest island in a camp site it was so quiet there and empty from tourists, the problem on the island is to find a good meal in the biggest town on the island for the lunch they had only eggs and bread. Another nice place, but not must visit is the botany gardens in Enttebe, Enttebe itself is very nice place and not far away from Kampala, it's the old capital and the location of the International airport, the people who heard about the mission in Enttebe can go to the airport and have a look on the old terminal, where the Israelis released the Israeli people from the terrorists, but not much left to see. There are many nice parks in Uganda in the west part and north-west to Kampala.
Where to stay
In Uganda forget the hot shower unless you plan to spent more than 10 US$ per day even in Kampala. In Kampala you can stay in the Backpackers hostel take from the Matatu station the car to Natete and ask from the driver to drop you down in the camp site, they have also dormitories and double rooms. In Bugala the largest island in the Sesse island I stayed in Horn Bill camp site, which is located on the shore of the lake and minimal equipment, but the place is nice and it's very cheap, in Kalinguala the largest village on the island there is another hostel where you can hire bycycles. I prefer the first time, because it got a private beach. If you on the way to see the Gorrilas and should stay one day in Mbarara, the university Inn is a good choise for camping since it's very nice place, but the rooms are not so cheap, if you have a student card show them and they'll give you small discount. There are also some small hotels in the center of the town