The development of iPhone OS 3.0 has been progressing nicely, and approximately a week after beta 4 was released, Apple has churned out a new beta, along with a new version of iTunes 8.2 pre-release.
Gizmodo is reporting a few changes in this new beta, despite initial reports that there were only bug fixes.
First and foremost, it is being reported that MMS is no longer available, and the methods used to enable it are now prevented. To add to this, apparently YouTube is now improved, in that it will stream a higher quality video to users on 3G, the same video that was initially reserved for those on WiFi. Lastly, there is changes to the StoreKit and various other fixes.
If you're a member of the Apple Developer program, you can head over to the Developer Center to download the new releases. For the mere mortals, you'll have to sit tight until OS 3.0 is released officially, or perhaps do a favor for a friendly developer.