The information you need is on this Google Maps page. There is probably one like this for MapQuest as well.
<a href=”http://www.google.com/apis/maps/gallery/mapsAPIProducts.html#utm_source=maps_home”>Google Info Page</a>
You need to use both sites’ maps API which allow you to pull code from your page…
Google Maps API FAQs are at http://code.google.com/support/bin/topic.py?topic=10028 and MapQuest OpenAPI FAQs are at http://www.mapquest.com/features/main.adp?page=developer_tools_oapi