I have heard of people taking a prybar and immobilizing the crank-shaft from the rear of the engine. I have never tried it and cannot vouch for how safe it is, or whether it can cause damage to anything. Apparently the pry-bar should be positioned to catch on a fly-wheel bolt. Sounds very dodgey to me, having never seen this method in action. Apparently you do this through the little plastic "grids" below the torque converter. Have no idea really.

Sounds a bit easier, if you can see everything.

Mabye someone else here has tried it.

I bought an electric impact wrench and it worked great on the flywheel. It has more than paid for itself on other projects. Make sure you get the biggist one you can find, if you take this approach. Sears has one that is made by Dewalt (the one I have). Also, might check a rental co.. Only problem is you have to pull the radiator to get enough clearance w/ the electrics. This is not too hard to do, though.