Great sites to play chess online for free

If you are looking for a great site to play online chess, I have a couple of recommendations and best of all they are both free of charge.

Buho 21 is based in Spain and offers the cleanest and best interface I have come across. Register, download the java application, and you'll be playing chess in no time. There is an active community of strong players, mainly from Spain and Latin America, and getting a game is no problem. There are a couple of downsides, the server was a little unreliable earlier this year, and the number of master players tends to be limited.

Following the server problems on Buho 21, I started playing at Chess Assistant. This is the playing site of the Russian chess database vendor. The interface is cluttered and non intuitive at first (like the ICC), but repays your perserverance. This is definitely the site if you want to play masters and even grandmasters on an almost daily basis. Finding an ad-hoc game can sometimes be slow, but there are countless tournaments you can enter throughout the day.