I read this interesting article today about a debug page installed in CRM 4 and CRM 2011. The blog post was on the microsoft CRM site, which you can read here.
Below is the crux of the article, it’s useful to find out what version you are using, where it’s installed etc.
Each CRM installation has an out-of-the box ASPX page that contains basic information regarding your CRM (verified for CRM 4.0 and CRM 2011) installation.
If you refer to the following URL:
http://ServerName:Port/OrgName/home/home_debug.aspx (replace ServerName, Port and OrgName to reflect your installation)
You will receive information regarding DataSource, Component Version Numbers, OrganizationID, etc.