there have been some requests from people attending FOSDEM that would like to go to the Betagroup Coworking to work on Friday and Monday. So they thought that it would be a good idea to host as many partcipants as they could... for
free!

Please see details and signup info here:
http://coworking.betagroup.be/hosting-the-fosdem-participants/ Space is limited and signup will be disabled when they reach their limit.

FOSDEM does not recommend any particular hotel or hostel. However, here is a list of popular accommodations for FOSDEM visitors to get you started. You can also check the mailing list for more information. wikitravel also lists some places to stay.

Hotels

Brussels has a large selection of hotels in every pricerange.