SQL Server Activity Monitor can help you identify locking and blocking issues. Closely watch the Wait Time, Wait Type, Wait Resource and Blocked By values for listed processes.

Sentrigo Adds Microsoft SQL Server Support to Its Hedgehog Database Activity Monitoring Software Major new release includes module for rapid implementation of PCI DSS, SOX, SAS 70 database compliance ...

Despite a few rough edges in the beta version, Entegra does a fairly complete job of auditing SQL Server activity.