Shrinking Transaction Log File in SQL SERVER

Sometimes it is necessary to shrink a transaction log in a database manually if the log file grows unexpectedly in order to save some disk space.

Here are the steps use to truncate transaction log in a database:

BACKUP LOG <databasename> TO DISK = '<backupfile>'
DBCC SHRINKFILE (<filename>, <targetsize>) WITH NO_INFOMSGS

e.g.:
BACKUP LOG NORTHWND TO DISK = 'C:\NorthwindLog.bak'
DBCC SHRINKFILE (Northwind_log, 100) WITH NO_INFOMSGS

To check your logical file name of your log file, you can run the query as below to get the logical file name something like 'xxx_log':
sp_helpdb '<databasename>'


More information:
http://msdn.microsoft.com/en-us/library/ms189493.aspx
http://support.microsoft.com/kb/907511