How can I fix a door that doesn't close because it doesn't fit the frame?
If you're having the same problem I had, and it's a case of rubbing but the door could be forced closed (so it's just slightly off), I just made a note of where it was rubbing with a bit of crayon (wipes off easily), then took a small hand plane to shave down that area slightly.

Unfortunately, I also made the mistake of passing off the plane to my house mate, who wasn't familiar with its use, and he ended up taking a chunk off of his bedroom door.  I have no idea how he managed to do it.  So, for using a plane -- you want long strokes, and try to shave the door off -- if it gets caught and starts splitting the grain, stop, move back further, and then lightly shave down past where you had the problem.