With the Mac App Store, getting the apps you want on your Mac has never been easier. No more boxes, no more disks, no more time-consuming installation. Click once to download and install any app on your Mac. The Mac App Store is now available as a software update for any Mac running Mac OS X Snow Leopard.
Hidden is like Find my iPhone, but for your Mac. When you activate tracking, Hidden will locate your stolen computer anywhere on the planet, collect photos of the thief and screen shots of the computer in use. And, best of all it's free until January 2011.
Sometimes you want to add media files to your iTunes so you can sync them on your mobile devices, but you don't want to copy the files to your /Music folder to avoid extra copies of the content and to save space on your hard drive.
In order to do that you can open iTunes Preferences and switch off Copy files to iTunes Media folder when adding to library.
If you want to transfer files from your Mac to a Windows PC or play your movies on your TV that accepts USB drives you will need to reformat your USB drive to a format that is widely accepted.
You can format any drives with the Disk Utility application, but the default Mac OS Extended formats will usually only work on Macs and the MS-DOS(FAT) format will only work on Windows XP and not on Windows 7.