cool virtual whiteboard service (also: planning poker site)

http://www.twiddla.com/ is a kind of awesome shared whiteboard... I remember trying to build something like this for my own use in 2001 or so, with Java applets and Perl CGI. Stuff like this can be so crucial for remote teams!

PS another useful site for scrum teams, especially with distributed teams, is https://www.pointingpoker.com/. It eschews fake cards for a simpler interface, but it's pretty effective.