Before going into the steps make sure the autogrowth property of the transaction log is set to a meaningful value.
Check to see if any huge transactions are still open and active.
Run DBCC OPENTRAN
--Try the following steps if the Transaction log doesn't get Shrinked :
· Take full backup
· Take log backup
· BACKUP LOG [<Database>] WITH TRUNCATE_ONLY
· DBCC SHRINKFILE (N'<log file>' , 50)