The backing up the Transactional Log file as part of the suggested MS SQL Maintenance Plans  should be reducing the size of the LDF file, but alternatively, you can perform an emergency “compact” the database using our tool.

Emergency Compact: 

Start Database Utility.

Press Next a few times until this screen.  Highlight your database name, then press the Compact button to recover all the space.

Be sure to check Include Truncate Transaction Logs, and press Execute.