Update on 7/29/2008: A much more powerful and integrated tool is released now as Power Tools. Check out screen shots, features and download: http://blogs.msdn.com/bharry/archive/2008/07/08/july-08-tfs-power-tool-preview.aspx
When I was going over past forum questions, I saw that many were having trouble creating filter expressions for event subscriptions, and managing subscriptions. We do have bissubscribe.exe tool that helps with creating subscriptions. But creating subscription expressions is hard because of its syntax. Also, that tool doesn't give a way to view existing subscriptions to unsubscribe them.
Sam, a formal WIT colleague, developed a tool to help creating workitem tracking subscriptions, but we couldn't make it a powertoy. I have attached the source for this as sample code in this post. This source can be built and this can be used as 1) a tool as described above and 2) as a sample to do basic operations with IEventService and ICommonStructureService interfaces.
Here is a screenshot on creating workitem change event expression. It works similar to workitem query builder, but without features such as grouping. The brackets for grouping can be added in Generated XPath textbox, and subscription can be created.
Here is screenshot that shows the existing subscriptions and a way to unsubscribe.
For FAQ on common problems with alerts & troubleshooting, check my post http://blogs.msdn.com/narend/archive/2006/07/27/679571.aspx
[update 4/2/07: Now there is a codeplex project at http://www.codeplex.com/tfseventsubscription to build another tool to achieve this]
//This posting is provided "AS IS" with no warranties of any kind and confers no rights. Use of samples included in this posting is subject to the terms specified at http://www.microsoft.com/info/cpyright.htm.