[plug] [OT]Flow Charting tool?

[simon at plumtek.com]

Hey all

Im after a simple tool to map programmatic flow through 'code units' which we
can declare seperately (ie to avoid redundancy) and which can accept notations
and linked files against the nodes.... man my terminology is bad :D

Basically a diagramming tool to link together predefined objects where we can
drill down into other documentation etc

Platform isnt important in this regard, in fact windows is preferred.

Anyone know of anything, even payware?