Q&A site Simplehelp has a novice-friendly tutorial that shows Mac users how to install Ubuntu Linux. You'll need three items: an Intel-based Mac, the Ubuntu OS (a free download, natch) and the latest Parallels build. (For the uninitiated, Parallels is virtualization software that allows Intel Macs to run other operating systems.) The tutorial shows you how to set up Parallels for Ubuntu, run Ubunt