You should be able to get the trial version here:
http://usa.autodesk.com/adsk/servlet/oc/offer/form?siteID=123112&id=10782497&ch=US dotcom&src=ADMR
The main page is here:
http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=6546938
I should have stated MapGuide Enterprise as that is now the name of the server product.
Regards,
Dave