How to show more than one places on google maps?

Using the publi开发者_运维技巧c google maps site, how can I show multiple locations on a map. I want to do this using the query string. For example, I might want to show Portland, OR and Seattle, WA.

http://maps.google.com/?q=Portland,%20OR%20AND%20Seattle,%20WA

I don't think it's possible on the Google Maps site, so you probably have to use the API and build a web page with two maps on it, each showing the location depending on the query. You might also want to look at the Geocoding API if you are going with that.