Knitting Chart Software?

[havocthecat]

I'm hunting for good knitting chart software. My drawing talents aren't all that, and I'm trying to create a Fair Isle design for at least a portion of the St. Trinian's school badge. I realize it's very complicated, but I'm mostly looking to do the shield logo with the "T" on it.

Anyway, I can't find any decent software, and I was wondering if anyone here knew of anything they could rec? Obviously, I would prefer not to pay for it, but I would be willing to do so to get the right software.

Thanks for any help you can give me!

St Trinians School badge - logo (clipped to polyvore.com)