I've seen this asked a few dozen times so I thougth I would put a link here so that I remember where I put it. INF: Consideration for a Virus Scanner on a Computer That Is Running SQL Server

Here are some good references on how to take care of your Transaction Log INF: How to Shrink the SQL Server 7.0 Transaction Log INF: Shrinking the Transaction Log in SQL Server 2000 with DBCC SHRINKFILE INF: Transaction Log Grows Unexpectedly or Becomes Full on SQL Server INF: Causes of SQL Transaction Log Filling Up INF: ...

This has been moved to sqlprogrammer.org.