GtkRadiant under GPL
gnarlin writes "GtkRadiant is now available under GPL license, along with some Quake II tools which never got a chance to be put under GPL before. Head over to the qeradiant website for all the details. GtkRadiant is a level editor developed by id Software and Loki Software. It is used to create maps for a number of computer games."
Radiant is already a very good tool to work with. The version that I used back when I was using it to make a mod for Call of Duty it did have serious crashing errors, though. I hope that fixing these bugs will be the first priority of whoever's interested in working on it.
For what it's worth, GtkRadiant is not exactly the same level editor as the one that was used by ID during the development of Quake: rather, it's a heavily modified version of QERadiant (Quake II's level editor) and Q3Radiant (Quake III Arena's level editor), which were used by ID.
...there's something better than BSP? Man, I need to get on that internet thing more often.... right after I clip this brush....