I came across this method while working at CSC Volpe. I like it because it does not require detaching the database.  Run the following from Query Analyzer while connected to the database you wish to truncate the log for.

sp_dboption ‘<yourDBName>’, ‘trunc. log on chkpt.’, ‘TRUE’


After running these commands run the Shrink Database task from within Enterprise Manager.  Your log file should now be about 1 meg.