There is a plugin out there called XML-Google Maps WordPress Plugin (probably rolls of the tongue better in the native German). It works but boy is it a struggle.
I would like to show a map just from a link to a google map but I could not get this to work. After installing the plugin you really need a gpx file to make a map display. To get a GPX file you need to get the GMap to GPX javascript doodad. Follow the instructions on this page to make a link in your favorites to the javascript that makes the GPX file for you. When you are viewing a google map and click this thing you get an xml file you can copy / paste into a file. Then in your WordPress post simply link to this file.
Its hard. Its clunky. I probably don’t really understand how to do this right but I’m trying to do this quick and dirty. If anyone has any advice please send it along!

