Check out leopardess' ADF article... I'm pretty sure it's in this forum, not positive though.
Edit: it was in the FW general discussion stickies.
http://www.myfishtank.net/forum/showthread.php?s=&threadid=23215
They don't need a very big tank, you could easily put a pair in a 2.5 (I've tried a pair, the second one always died for me). I've heard that they aren't good in tanks over 20g, because they are pretty slow eaters and they tend to starve if they aren't specifically fed or hand fed... they get outcompeted very easily. Plus in bigger tanks you tend not to see them a lot. They can be single, but I've heard people say they are much more visible when they are in a pair or group. They don't fight with each other to the best of my knowledge. They also don't fight with fish... so they are fine with anything that doesn't attack them. Make sure not to get an African Clawed frog instead of a dwarf, because the clawed frogs get much bigger and eat/attack other fish. Dwarf frogs will have webbed front feed, the clawed will not have webbing on the front feet. Also, albino frogs are almost exclusively clawed. Not sure on the current... they need to be able to get to the surface to breathe, but they spend the majority of the time sitting on the bottom (sometimes they float, but I've never had a floater). They probably appreciate some current, but not blasting current. They swim kinda funny like... they are cute little suckers.