What algorithms are good for interactive/realtime graph-drawing?

Question

What algorithms are good for interactive/realtime graph-drawing for live data and direct-manipulation?

Failing that - what libraries do you use to draw graphs?

Answer 1

I use the Dot language to describe graphs. And, the Dot compiler's output includes SVG, which is in XML and can be embedded in XHTML.

http://en.wikipedia.org/wiki/DOT_language