This is a great plugin... the best I've used for google maps, especially because it can be used in custom post types!
The problem I'm having is that in IE, the map will not center. The whole map is visible, but the center I set in the map configuration box ends up being offset to the top left corner.
In Firefox, it's even worse. Not only is the center LatLong pushed to the upper left corner, but only a little square of the map is visible in that corner (the rest of the 900x400px map is gray). However, all the controls are still displayed in the right places.
The only reason I can think of is that I'm running Google Maps Made Simple (GMMS) 0.5.6 in a local WordPress 3.2.1 installation using WAMP server 2.2.
I'm wondering if anyone else has/had this problem (or can confirm it's happening because I'm running WP/GMMS locally) and if there is a fix from the developer (or advice from someone familiar with these types of issues on WAMP server).