Apple has today released the third version of its iOS 5 beta. The new version should offer some stability improvements and bug fixes.

The iOS 5 beta is available for download now on the Apple Developer site. Note that Apple requires that you have a developer account and a device registered on the site in order to download and install iOS 5.

In addition to iOS 5 beta 2, which is build number 9A5259f, Apple has also released iTunes 10.5 beta 3 for Mac and a new iCloud beta for Lion as well as Xcode 4.2 Developer Preview 3.

Devices running iOS 5 beta 3 can sync with iTunes over WiFi, but the new version of iTunes beta is not compatible with devices running beta 2. That means that you need to sync your device before upgrading iTunes, upgrade your device, then sync it with iTunes again to restore from your backup.

There are a host of minor bug fixes, but these are the salient points:

  • You can now set a custom SMS message tone and purchase new tones.
  • New icon for Reminders app
  • After restoring, you may not be able to back up again because the device still thinks it’s restoring. To workaround this issue try syncing apps or media that are missing form iTunes or try deleting your iCloud account and adding it back.
  • If you delete your backup, the feature will be disabled but settings may still indicate that it is enabled and you will have to toggle the BackUp to Cloud switch in Settings.
  • For compatibility reasons, this version of the iOS 5 beta requires that all files be backed up again, instead of only those files that have changed since your last backup. This may cause a warning that your account is over quota. In case the warning occurs, you can delete your oldest backup to free up space and then initiate a backup.
  • iCloud Storage
  • During the iOS 5 beta period, any documents stored on the servers might be purged periodically before GM. Therefore, it is highly recommended that you do not store any critical documents or information on the servers.
  • iMessage beta 3 will be unable to communicate with iMessage users on beta 1. It works between beta 3 and beta 2.
  • Modal alerts don’t appear for iMessages.

iOS 5 is the next major revision to Apple’s software for iPhone, iPod, Apple TV and iPad devices. The new OS is slated for release in the fall of this year. You can see our complete rundown of the iOS announcements at WWDC here. We’ve also got a closer look at some of the features of iOS like iMessagesTwitterSetup and Notification CenteriCloud and alerts.