You should also check out darwinports for package management (
http://darwinports.org/), it was inspired by FreeBSD's port system. I prefer it to fink. Vinod Kurup recently posted his port for installing OpenACS. You can find instructions here:
http://kurup.org/openacs/darwinportsI just saw a mention of a DVD training video for Windows switchers today. You can find it here: http://terrywhite.tv/
Good luck. You won't regret it.