What is the easiest kind of visa to get from Uganda to the US?

I second Ernie's answer above. Go through the legitimate K (fiance) visa process. Do NOT use the B/visitor visa for this. Qualifing for a B visa means that the applicant intends to return to Uganda (or the home country) after a temporary visit to the U.S. If he knowingly uses a B visa to come to the U.S. for the purpose of marrying an American citizen and/or to stay then he could jeopardize his status in the U.S. and possibly be deported. At the least it could greatly complicate the entire process. In addition, when foreign citizens abuse visitor's visas in this way, it makes Embassies more reluctant to issue such visas to other Ugandans or citizens of similar countries, even when they might be legitimate visitors. It extends the bad reputation of illegitimate travellers and increases the difficulty for others to obtain legitimate visas. Don't abuse the system.