Go to Area51 (Idiots Guide: Installing [ROM][STABLE]AreaRom v2.3 - Android Area51 ) It's a pretty detailed set of instructions to download Odin and the ROM and get the ROM installed. (If you first partition your SD card to include an ext4 partition, but no swap partition, you'll have a lot more "internal" memory for apps. I'm currently running with a 2GB partition and, even though I have a bunch of apps I'm going to uninstall [I try a few different apps for anything I need to do, to see which one is better for my needs], I still have almost 1.5GB free.)
The CM7 ROM at that site is also nice - but the GPS receiver won't work with that one, so you're limited to wifi and cellphone tower location service. Not bad if you don't need GPS, though.