I’ve been playing with The New York Times’ Visualization Lab lately and am enjoying it quite a lot, even though the current data sets you can play with are quite limited. However, the system uses IBM’s ‘Many Eyes’ tool, a project of their Visual Communication Lab, and if you head there you can register and upload your own data sets.
On the topic of data visualisation, I’ve also been going through the archives of Pictures of Numbers (via Kottke); a site providing “practical tips and techniques for busy researchers on improving their data presentation”. It reminds me somewhat of Junk Charts.
(A good resource for ‘info viz’ links is the ‘Bookmarks’ section of Eager Eyes… far right sidebar, under the login box.)