Country Specific Information for uganda.htm is a good place to begin looking at issues of Uganda adoption.
If you are adopting independently, working directly with an orphanage or through a foreign facilitator, be aware that not all children in orphanages qualify for immigration as "eligible orphans", under U.S. law. If you manage to adopt a child who does not qualify, you will not be able to get a visa for him/her to enter the U.S., unless you live overseas with him/her for at least two years. It is always best to work through a qualified American agency if you have limited familiarity with U.S. immigration laws.
Sharon