^
FICS is the best for free chess games with 'normal' time controls.

You need a client application to play at FICS, there are some good options. You can play from your browser (requires a Java installation if you lack it), or one of the clients they link to at the Free Internet Chess Server (FICS). I like Winboard, but many aren't happy using a client without a seek graph for instance, I never mind, I always used the console to begin with. Winboard isn't specifically meant for use with online chess servers, which I like, it also makes a decent default PGN reader and it can work in combination with Crafty..
Babaschess is pretty popular at FICS, then there's the quite similar Jin (I used it for a while before concluding all I needed was in Winboard) and I liked Jin, similar to both these is Thief.. If you've ever used the ICC (internet chessclub) software, Dasher or especially BlitzIn, you'll note the abundant similarities. If you can use one of these, you can use them all.