<?php echo GeoMashup::map( 'map_content=global&object_name=user&marker_select_info_window=true&height=450&width=260&zoom=auto&add_overview_control=false&add_map_type_control=false&marker_select_center=false&add_google_bar=false&marker_select_highlight=false&map_control=GSmallZoomControl' ); ?>

http://code.google.com/p/wordpress-geo-mashup/

Use this code to display a map of all users on your wordpress blog.

Displays users on a map on Wordpress MU and Buddypress

PHP