What should I know before moving to Kampala about daily life? There are a million things I could tell you, but I'll stick to one word: COME!
Kampala / Uganda is a great place, I've worked here 3 years and I love it.
generally cost of living in Uganda is low but expats can spend as much as you like, i.e. there are expensive bars and restaurants if you have the money to spare. Accom can take a little while to find, the city is growing quickly. Get someone here to find you something, ideally same side of town as where you work.
There is loads to do socially. Bars weekends away, to the lake or on Safari in the evenings there are social clubs that include salsa, Scottish dancing, poetry, running (I'm a Hash House Harrier, for ex), the list is endless. Kampala is a very accessible town and safe but traffic can be a nightmare (most days).
We have DSTV and a number of mobile phone operators, including MTN, Warid, orange and UTL. Internet speed is improving and you can usually Skype.
There are a number of shopping malls (personally I don't like them, but they can be convenient) and big-name supermarkets like GAME and ShopRite. I would say that you can buy anything in Kampala these days, although it may be more expensive than you're used to paying (and it may be cheap rubbish!)
As for what life is like in Uganda, feel free to check out my blog [url=www.muzungubloguganda.com]Diary of a Muzungu.
Good luck!