Because of active portions of the log, the process I usually follow is:

1) truncate

2) shrink

3) shrink again

4) shrink... please!

5) SHRINK damn you!

6) ok, this is your last chance... SHRINK!!

(mutter under breath)

7) detach db

8) rename LDF file

9) attach db specifying just the MDF (let it create a nice new LDF)

Cheers,

- Mark