Krein, found this on the Google site; based on what I read, I'll bet that Google would not object to your using their maps. I notice that they are reserving the right to add advertizing in the future, so that suggests what their business model will be for the product.
Larry
http://code.google.com/Google Releases Maps API for External Use - 29/Jun/2005
"I'm very happy to let you know that our friends who have created Google Maps have released an API so that you can post interactive, draggable, zoomable, maps (with satellite imagery) on your personal websites.
For more information, check out the Google Maps API page and be sure to join the Google-Maps-API Google Group. A huge congratulations to the maps team for doing this."