Lazyweb request: dependency grapher?

Would anyone happen to know of something that makes it easy to graph
dependencies, preferably interactively? I’d like it to be ridiculously
easy to split an entity into two entities A and B, while preserving
the inbound connections for A and the outbound connections for B. This is for a crazy goal management thing I’d like to have… =)

If it’s open source and keyboard-friendly, that would totally rock. If
not, well, I’ll sit down one of these vacations and hack something up.
Maybe Christmas. (Only two months away! eek!)

Random Emacs symbol: message-unix-mail-delimiter – Variable: Regexp matching the delimiter of messages in UNIX mail format.