Something to remember -
BisSubscribe.exe is the command-line tool for maintaining alerts for Team Foundation Server
This tools is installed on the server, and by default ends up in the following path:
C:\Program Files\Microsoft Visual Studio 2005 Team Foundation Server\TF Setup
Supposedly, you can list all the events that can have alerts attached to them by using the web service on the TFS box - eg.
http://localhost:8080/Services/v1.0/registration.asmx/GetRegistrationEntries but this fails with an exception for me.