Mac

How to password protect your Mac with the screen saver
I would have never guessed that Keychain Access provides a menu bar item to quickly do this.
BitRocket, a cute open source Mac BitTorrent client
Uses Google Code to host the source.
Take Control of Podcasting on the Mac
$10 US ebook covers all the basics.
Part 1 of Adrianna's complete Mac (student) life
Some good tips from a self-described "half-hearted practitioner of GTD".