We have now published the code that Boris Scholl demonstrated at TechEd 2008 – showing an AJAX web part feeding from a PSI Extension and showing the location of each project on your server – where the city of execution is held in a custom field.  The end result looks like this:

image

Hovering over the pushpins shows details for the specific project – also returned by the PSI Extension.

The code is on the MSDN Code Gallery at http://code.msdn.microsoft.com/PSVR2007AJAXWebPart so go along and try this yourself.  The document there covers the creation of the web part – and the code for the PSI Extension is also included.  You will probably need to also reference the SDK for PSI Extension deployment details.  Enjoy!