For reference, the old Atlas Games Delphi forum's read-only archive can be found at atlas-games.com/forumARCHIVE/index.html. Many basic questions about Ars Magica may already be answered there.
The link to the read-only archive of the old forums is broken. I hope it can be fixed/recovered, the amount of great content on the old forums was nigh priceless in my opinion!
It seems that Delphi deleted the old forum files, and didn't reply to my email asking if it was recoverable. So I'd pretty much given up hope. Then, cleaning out old files on my computer today, I stumbled on a backup compiled by Fruny in 2005! A little bit of html formatting later, and it's up and readable on our own server now! I've updated the link above. Enjoy!