Check out Handgunlaw.us
. There's an interactive map that will show you who reciprocates with a particular state. To the left, in the navigation bar, there's an option to create your own map. You can choose which states you have (or might get) permits in, and the map will show where you're covered.
As I'm sure you already know, you're still responsible for obeying whatever laws are in place for each state (Excedrin headache number .45). The site also has pretty good information on state laws. But I would still try to find the statutes on each state's website, since those will be more up to date.
Plus, it's just a pretty informative site all around.