In SQL Server 2000 and earlier, identifying blocking issues was not an easy task. One option was to use Enterprise Manager to view existing connections to see if any blocking was occurring, or using the sp_who or sp_who2 commands. If you were really ambitious, you could write some code to extract blocking data from system tables.
In SQL Server 2005, the situation has improved. Besides Management Studio, stored procedures, and system tables, we also have DMVs and even the Performance Dashboard. However, most importantly, we have a new SQL Server Profiler event, Blocked Process Report. This event does a great job of helping you to identify blocking issues and, at the same time, provides you with much of the information you need to help correct the problem.