It has been frequently seen in SQL Server, that despite the efforts of the DBAs, the Log Files will refuse to be truncated. However, the following snippet of T-SQL is most effective on it’s own.
USE DatabaseName
GO
DBCC SHRINKFILE(TransactionLogName, 1)
BACKUP LOG DatabaseName WITH TRUNCATE_ONLY
DBCC SHRINKFILE(TransactionLogName, 1)
GO
These are just a few of the sites I went to doing my research:
http://ss64.com/sql/dbcc_shrinkfile.html
http://msdn.microsoft.com/en-us/library/aa258824%28SQL.80%29.aspx
http://blog.sqlauthority.com/2010/05/03/sql-server-shrinkfile-and-truncate-log-file-in-sql-server-2008/
Greynault's Blog 