CAIDA,

http://www.caida.org/home ie the Cooperative Association for Internet Data Analysis, have been active in this domain for a while; some of the most spectactular 2d visualizations i have seen come from the site above.

one of their tools is geoplot:

http://www.caida.org/tools/visualization/geoplot/Demo/GPDemo.html

an *applet* <sigh> which *thankfully* has a perl API that allows you to add nodes , links, paths etc on the applet. very kewl. of course, different maps can be specified, but i dunno if this is at the perl API level.

here is the link for the perl API:

http://www.caida.org/tools/visualization/geoplot/API/

best of luck, /msg me if you have success/probs -