There's the free AVI2DVD, but it does take a bit longer than the commercial programs and sometimes might have audio sync issues, but for free, hey?
The fastest is probably 1ClickDVDMovie from LGSI, can do that 3 hour avi in maybe an hour to an hour and a half...and the quality will be great with no audio sync issues.
VSO's ConvertXToDVD also is a great program and is just as good as 1ClickDVDMovie.
TMPGenc is another conversion program, but I didn't care for it's output very much.
There you go, a few to check out. They all come with free trial periods...