Ausman,
Just changing the recovery model to simple does not truncate the log....I think it has to wait for the next checkpoint to happen.
Also, I have noticed that if you haven't done log backup in a while and if the log is big, you have to do log backup couple of times and then shrink the log in order to free up space.
Please let u know how it went.
Thanks,
SueTons.
Regards,
SQLisAwe5oMe.