iTunes 10.5 Released

If you're planning on downloading iOS 5 tomorrow, you'd better update iTunes first. If you're a Mac user, it's as simple as going to Apple (in the top menubar) and clicking "Software Update...". If you're a Windows user, you can find the Apple Software Update application (probably in your start menu), or just re-download it from Apple here.

The update is necessary for iOS 5, and also brings iCloud, Automatic Downloads, the ability to download previously purchased content with ease, and enables WiFi syncing with iOS 5 devices.
via MacRumors