This is an ancient thread brought back from the dead with some really bad advice in it. There are very complete threads on how to remove the crankshaft bolt. Many are stickied.
The best one is by DZ63 and the link is here:
DIY: GEN3 Timing Belt + Waterpump + Oil Seal Change - Part 1
DIY: GEN3 Timing Belt + Waterpump + Oil Seal Change - Part 2
In it there is valuable information on how to remove the crank bolt. DZ63 makes an over the top tool to do it, but many others have made less sophisticated ones from parts readily available.
But by far the easiest way is the Starter Bump method. Search the forums and you will find many threads on how to do it correctly. Here's what I did to make a home made tool to hold the bolt cranksaft pulley to tighten it. The tool can be used to loosen the bolt, but it isn't necessary. The easiest way to remove the bolt is to use the Starter Bump method. Don't be an idiot and try to hold the breaker bar as one person did. A link to the video is posted in the thread.
2000 Camry LE 6cyl 1MZ-FE Timing Belt Change
If you use a chain you risk damaging the crankshaft pulley. I'm guessing that people that use chain wrenches don't know that the crankshaft pulley is not one piece. In fact it is make out of two concentric rings separated by a thin strip of rubber. The purpose of the rubber is to isolate the engine vibrations from the pulley system. If you use a chain wrench to hold the outside ring, and attempt to loosen the crankshaft bolt, which is on the inside ring, you can easily break the rubber seal, and if that happens you are in deep grease. The pulley will wobble quite badly, it will slip, and very quickly the crankshaft pulley will destroy itself, and a new one costs $350-$375. So using a chain wrench sounds like a good idea, but now you know the risks of using one.
The torque specs to tighten the crankshaft bolt on the 4-cyl is 80 ft/lbs and on the 6-cyl it's 130 ft/lbs. I have no idea why there is such a big difference. Most impact wenches can do 80 ft/lbs so you really don't need any home made took to either tighten or loosen the bolt. You will, however need some sort of tool to hold the crank pulley to tighten the 6-cyl bolt to the 130 ft/lbs.
Some people with a 6-cyl have just put a little blue Locktite on the bolt, and tightened it with an impact wrench and have reported no problems. The crank pulley is tapered, and keyed, so it really can't go anywhere. I'm guessing that the engine rotation over time tends to tighten the bolt, but YMMV. If you want to be sure, then you will to fabricate some sort of tool to hold the crank pulley while you torque it to specs if you have a 6-cyl.