freeze plug??

I have a 1997 G.M with 190k miles. It started to lose coolant and I saw it dripping from the back of the engine underneath. Then it just strwams out and it eventually gets way too hot and it cant be driven. I was told its a freeze plug in the back of the engine that you hae to take the tranny out to replace it. How much does it cost to have someone do this? or should i just not fix it

http://www.ebay.com/ Search freeze plug tool
They do make ones you install with a box wrench. Rubber plug I don't like these.
If you can get it in without pulling the engine I would try. Four jack stands, and a floor jack are required.

Parts are cheap, labor is what will get you. Call around and get a few prices and then determine if you want to tackle it.