iTunes

Here’s some info about the new iTunes9!

Mac computer with an Intel, PowerPC G5 or G4 processor
Intel, PowerPC G5 or 1.0GHz PowerPC G4 or faster processor is required to play Standard Definition video from the iTunes Store
2.0GHz Intel Core 2 Duo or faster processor is required to play HD video, an iTunes LP, or iTunes Extras from the iTunes Store
512MB of RAM; 1GB is required to play HD video, an iTunes LP, or iTunes Extras
Screen resolution of 1024×768 or greater; 1280×800 or greater is required to play an iTunes LP or iTunes Extras
Playing videos also requires at least 16MB of video RAM
Broadband Internet connection to use the iTunes Store
Apple combo drive or SuperDrive to create audio, MP3, or back-up CDs; some non-Apple CD-RW recorders may also work.
Apple SuperDrive to back up your library to DVDs; some non-Apple DVD-RW drives may also work.

Mac OS X version 10.4.11 or later; Mac OS X version 10.5 or later is required to play an iTunes LP or iTunes Extras
QuickTime 7.6 or later
Support for HE-AAC requires QuickTime 7.6.4 and Mac OS X version 10.5 or later
Safari 4 or later
200MB of available disk space

Now for the info on the windows version

Windows XP Service Pack 2 or later, or 32-bit editions of Windows Vista
64-bit editions of Windows Vista require the iTunes 9 64-bit installer
QuickTime 7.6.4 (included)
200MB of available disk space
Screen reader support requires Window-Eyes 7.0 or later; for information about accessibility in iTunes, visitwww.apple.com/accessibility

iTunes