I found this link via Andrew Gelman's blog the other day:
I haven't had much of a chance to play with it, but it looks like it could be useful. I've had a few instances in class this semester where I've wanted to make some maps of the US to illustrate various points, but alas, have not known how to do so. Rather, I've wanted to make customizable maps, but have not known how. It seems like this program is pretty simple to use–just drag and drop a CSV file with the relevant data onto the map. It also appears to be able to perform some basic data manipulation as well. When all is as you wish it to be, you can export an image file of your customized map to incorporate into documents, presentations, etc.
As the link suggests, this appears to be only for Mac users at the moment. I'm sure there must be some freeware out there that accomplishes the same thing for PC users as well. I'm generally behind the curve on this kind of thing, so if anyone is aware of the existence of such software please post a link in the comments section. Also, if anyone is aware of similar software that can be used at the global level that would also be most useful.