add "proxy=localhost:9050" (assuming tor is listening on 9050) to bitcoin.conf
If you want to be more paranoid, also add "nolisten=1"
nolisten is absolutely irrelevant, if you connect over a proxy/tor then you got the IP of the proxy, therefore others may try to connect to the proxy and not to you!
compile ufasoft's bitcoin miner is kind of tricky, you have to read the whole ufasoft btc miner thread to get it done (and some other), i got a build for 32bit and 64bit here (32bit compiled on debian sid and 64bit compiled on Ubuntu 10.10 (maverick)).
Overall you have to get jwasm, edit one or two cpp (i guess it was the sha256sse.asm) and the makefile.
move the bitcoin-miner.exe to C:\ then press Win + R and type cmd, press enter. Now u got a winblows console, type in "bitcoin-miner.exe --help" wihtout the quotes and enjoy
EDIT: i forgot, before you type in bitcoin-miner.exe --help, you have to type cd C:\