Download iTunes 10.5.1 Beta 2 - Windows - Mac

Along with iOS 5.0.1, Apple has also released iTunes 10.5.1 beta 2 for developers to continue iTunes Match beta for developers living in the U.S.

iTunes 10.5.1 release notes follow as:

iTunes 10.5.1 beta 2 includes a number of important stability and performance improvements for iTunes Match, and is a required update for all subscribers to iTunes Match beta. iTunesMatch is now also available on your Apple TV.
Your iCloud libraries will be deleted at the end of this beta.
Backup regularly and do not delete the music you add to iCloud from your computer. Apple may periodically delete all iCloud libraries during the beta period. This will require you to scan, match, and upload songs again.
About Subscribing
iTunes Match beta is available to iOS developers in the United States.
iTunes Match beta is available as an automatically renewing subscription for $24.99 per year. You may cancel at any time from your Account settings.
You can subscribe to iTunes Match using iTunes 10.5.1 beta 2 on your Mac or PC. You cannot subscribe to iTunes Match from your iOS device or Apple TV.
You can access your music in iCloud on your iPhone, iPad, iPod touch with iOS 5, or your other computers with iTunes 10.5.1 beta 2.
You can access your music in iCloud on your Apple TV with builds 4.4, 4.4.1, or 4.4.2.
Once subscribed, you can add up to 25,000 songs to iCloud, and your iTunes purchases do not count against this limit. iTunes Match will not add your apps, books, movies, TV shows, ringtones, and audiobooks to iCloud. These items can continue to be synced to your iOS device with iTunes. iTunes LPs and iTunes Extras are also unsupported.
iTunes Match includes limits to how you may access your music in iCloud:
You can use iTunes Match on up to 10 computers and iOS devices, up to five of which can be computers authorized with your Apple ID.
You can use iTunes Match simultaneously on 2 Apple TVs.
You can only associate computers and devices with a different Apple ID once every 90 days.
Getting Started
To subscribe to iTunes Match:
Install iTunes 10.5.1 beta 2 on your Mac or PC.
Open iTunes and choose Turn On iTunes Match from the Store menu.
Click the Subscribe for $24.99 button and follow the onscreen instructions. Once complete, your Music library will include songs on your computer and in iCloud.
Once iTunes has completed matching your music with songs on the iTunes Store, you may begin accessing your music in iCloud from your other devices:
From your iOS device:
Tap Settings > Music > turn iTunes Match ON. This will disable syncing music with iTunes.
Press the Home button and tap Music.
From your other computers:
Install iTunes 10.5.1 beta 2 on your other Macs or PCs.
Open iTunes and choose Store > Sign In. Sign in using the same Apple ID you used to subscribe to iTunes Match.
Choose Store > Turn On iTunes Match.
Click the Add This Computer button.
Once complete, your Music library will include songs on your computer and in iCloud.
From your Apple TV:
Install Apple TV 4.4, 4.4.1, or 4.4.2.
Sign in to the iTunes Store on your Apple TV using the same Apple ID you used to subscribe to iTunes Match.
On your Apple TV tap Music > turn on iTunes Match.
Once complete, you will be able to play songs in iCloud on your Apple TV.

iTunes 10.5.1 beta 2 with iTunes Match (Mac)
iTunes 10.5.1 beta 2 with iTunes Match (Windows)
iTunes 10.5.1 beta 2 with iTunes Match (Windows 64)