Sorry can't recommend a charter there, but going by the amount of big fish we saw when we went diving you shouldn't be disappointed. As Jewhunter says the night markets are the best. Also remember that plastic bags are banned and they may search you when you get off the ferry. If you are going to Uganda try a charter for Nile Perch at Jinja. A bit further south Namibia has some ridiculous fishing along the skeleton coast. Kob are jewfish on steroids.
If you want any info on what to expect in any of the countries, not just fishing wise, send me a message, spent 3 months travelling Africa last year.
ps . still waiting to get the boat....
Alasdair