Getting into Bwindi Impenetrable National Park requires a permit - the best place to get that is from the Uganda Wildlife Authority UWA. They have an office in Kampala, on Kiira Road. Check out the (http://www.uwa.or.ug). Tour operators can also make reservations, but you only pay on arrival. There is no point in going to Bwindi without a permit, as you will be refused entrance.The best way to get there is to get a bus from Kampala - the daily Post Bus takes about 8 hours from Kampala to Kabale, a nearby city with several hotels and hostels. From there you can arrange private transportation, for which you have to reserve another day of travel - leave early in the morning; you'll need to get transporation to Butogota, and from there to Buhoma, where hotels are available only a short walk from the starting point of the UWA gorilla tracking.
www.bahr-el-jebel-safaris.com has both winged safaris and ground safaris to see the gorillas.
