There is an online system for hotel reservations. In the web form, you should select "Freiburg" for the area and the destination field.

The online reservation system is provided by

Freiburg Incoming Touristik (FIT)
Am Bischofskreuz 1
D-79114 Freiburg
Phone: +49 761 / 88 581 - 145
Fax +49 761 / 88 581 - 149

Should you have any problems with your hotel reservation, then FIT will be glad to advise you via email or on the phone (+49 761 / 88 581 - 145). Their phone hotline is accessible Mon - Fri, 8:30am - 8pm and Sat, 9am - 16pm.

A cheap alternative (13 - 28 €) is the Black Forest Hostel. The hostel is in walking distance from the city center and the main train station; alternatively, you can take tram no.1 to "Littenweiler", get out at "Oberlinden", and walk from there.

Are you looking for someone to share a hotel room with during ICFP /IFL 2007? Then you can use this wiki page to find a room mate. You need to create an account before you can edit the page.