if you just want decent BEER (not lager) then almost every little pub in Bath will sell a variety of different wonders for you. For continental swank then head up the main stretch (somewhere like raphaels [sp?] is more of a restaurant but it's good). bath gets more expensive the higher you get generally so you can't really go wrong.
Because Bath's so nice to look at all the decent establishments have glass fronts, so you can see what you're getting before you go in there. Bath's small so you can probably walk across it in 15/20 mins, just go for a wander and ask a local or 2. expect the girls to be snotty though, if that's what you're after.
B@Th*nG