Today Apple released iPhone OS 3.0 Beta 3 (Build Number: 7A280f) and the SDK for the new firmware. Some changes from Beta 2 to Beta 3:

• MMS works with modified carrier bundle on German T-Mobile network.
• Spotlight now saves the last search.
• Speed improvements.
• Option for iPods that let you change what your double tap home button is.
• You can change spotlight to search for what you want to search for ex everything but applications.
• iPod icon is aligned.
• Restrictions now add In-App Purchases and Location.

(changes reported by 9to5mac.com)