Just compare the color of the wires on the first pin on each side. Assuming that the cable works at all, same means straight, different means crossover.

Not quite. Just before I left for the NY/NJ empeg meet this spring I tossed what I thought was a crossover cable into my bag, and grabbed my laptop, just in case someone had a use for it.
Sure enough, someone wanted to upgrade to 2.0final and HJ. Can't remember who it was, but anyway. I discovered that my bag contained the straight cable that it always did, and this strange bastard cable - neither of which would work (obviously).

I've since discovered that Cisco management/console cables are sometimes implemented using a 9 pin D to RJ45 adapter and regular cat 5 cable... the cat 5 is wired so that one end is the mirror image of the other, and is known (to Cisco anyway) as a Rollover cable. And that is what I had in my bag.