I have mentioned some of these links before, but they are worth bringing back to the top.
1) Superdelegates: Why do 796 individual Google searches to find out who is supporting Clinton or Obama when the work has already been done for you? 2008 Democratic Convention Watch has been updating the list of committed superdelegates throughout this campaign. If you want a more graphical representation of the data be sure to check out the superdelegate map on Google Maps and/or the superdelegate layer for Google Earth. [Big thanks to superdelegates.org for the links.]
2) Electoral College: In response to the recent rash of electoral college maps that have appeared on FHQ comparing Obama and Clinton's chances against McCain, we received a link to fivethirtyeight.com. Just a solid, solid site doing a lot of the same things the maps here have done, and in some cases better.
3) 2008 Election Data: If you haven't checked out Tom Holbrook's site, be sure and stop by for a look. He provides some nice analysis of the voting behavior trends witnessed during this cycle and what that may mean as the nomination phase continues.