Gary Price (and Barry Schwartz) write about embedding Ask City Maps in 3rd party sites. Google offers a similar feature. Both Ask City and Google offer customization so you can create a customized display on your map and then embed that map in your site or blog.
Here’s an example of a hotel search in New York in a customized area I created with the Ask drawing tools:
This is very simple to do and represent “mashups for the rest of us.” Gary has lots more information in his post (i.e., enhanced walking and driving directions).
Screenwerk 