How do you deal with multiple locations?
I've been using GMap + Location to accomplish this.  The site I've been working on involves Apartment Communities spread out all over the place.  I created a content type for apt_community which accepts location data (I only allowed an exact address but you can let the user pick a location on a map).  Then I have a view that puts all the points on a map which I attach to a page.

Check this DrupalTherapy screencast on GMap + Location (http://www.drupaltherapy.com/gmap) and this other screencast Drupal Aficionado did on using GMap and Views (http://blip.tv/drupal-aficionado/gmap-location-and-views-1773822).