Apple has posted iOS 5.1 beta 2 (build 9B5127c) to developers fixing the battery draining issues apart from fixing minor bugs in addition to other security improvements over iOS 5.1 beta 1 released two weeks back. It appears that you can now delete photos from Photo Stream from your iOS device.
No new feature has been mentioned in iOS 5.1 beta 2 change log released by Apple but, developers have independently started digging a little deeper into iOS 5.1 beta 2 rigs. Before you download and install iOS 5.1 beta 2 on your iOS device, it is highly recommended to take a backup on your iPhone, iPod touch or iPad.
Developers looking to have their Apps updated before iOS 5.1 is available for download can head to the Apple Developer site ($99/year Developer Program required) and download the iOS 5.1 beta 2 9B5127c for iPad (3G, WiFi), iPad 2 (3G, WiFi), iPhone 4S, iPhone 4 (GSM, CDMA), iPhone 3GS, and the 3rd and 4th generation iPod touch models.
In case you are not registered, you can still follow the direct links listed below to download bits of iOS 5.1 right now.
Download iOS 5.1 BETA 2 direct links
iPhone 4 (GSM)
iPhone 4 (CDMA)
iPad 2 (Wi-Fi Only)
iPad 2 (3G)
iPad 2 (CDMA)
iPod Touch 4G
iPod Touch 3G
Apple TV 2G