Does anyone know where to find the sheet metal or tin plates with holes in them that are used for fireblocking around 1 1/2", 2" PVC pipes, and copper water lines?
I've seen them in 2 different houses and I was talking to one of the building inspectors and he was telling me that he wants to see no more than 1/8" gap around pipes going through the top plate in a finished basement. I couldn't find them at Lowe's.

You should be able to find them through a local Plumbing wholesale house.

Check your Yellow Pages.

A cheaper and usually acceptable alternative is a fire blocking caulk (http://paint-and-supplies.hardwarestore.com/50-269-specialty-caulks/flamebuster-silicone-heat-fire-block-caulk-650434.aspx).

Check again with the inspector to make sure the caulk is an acceptable alternative before buying or applying it.

Thanks a lot guys. The building inspector mentioned Rock Wool but said it had to be held in place so it couldn't fall. I figured the caulk woud be more expensive but maybe not.