Tech tree display?

[Phoenix-D]

OK, here's the problem. I'm attempting to totally re-work SE4's tech tree, and to some extent the combat system. Not adding anything new yet, just fiddling with what's there.

Anyway, I've been drawing out the actual tree, you know, tech name then lines to what it gives. The problem is I need to show this thing to others (for feedback), and scanning my scribbling in is.. less than effective.

Don't suppose there are any programs out there to help with this sort of thing? A simple flowchart program might help, but the ones I've found have been loaded with extra crap and slow usage.

Otherwise, I'll end up having to do stuff like this..

Physics
-shields
--shield I-V, phased shield I-V
--anti-shield weaponry
---shield depletors/distrupors
---phased weapons
-laser weapons
-armor

Chemistry
-armor
-explosive weaponry

Which doesn't look bad for that, but picture the entire tech tree like that, plus multiple interdependant branches..

Phoenix-D