Via Ajaxian: JGraph has release MXGraph, a direct manipulation visio-like beast. The web site says it’s a thin-client component on top of JGraph (if you’re not familiar with it, it is a — shocking — Java desktop visio-like beast). It has some nice things in it, such as a nice marquee selection tool and draggable everything. There are some small defects, like drag from the pallette not working quite right. Still, a very impressive piece of code (even if the code is obfuscated).
JGraph is open source, but some of the cooler stuff, like advance automatic layout, comes in the commercial Pro version. It’ll be interesting to see what the licensing terms for the MXGraph component ends up being.

Hi,
have seen a additional LGPL ajax javascript drawing and graph
library on Open-jACOB ( http://www.openjacob.org )
or Open-jACOB Draw2d ( http://www.openjacob.org/draw2d.html ).
greetings
Andreas
Draw2d + Yahoo UI
Demo: http://www.openjacob.org/draw2d/single/YahooUI_integration/index.html
greetings
andreas