Also, it is confirmed that a baseband update is present for your 3g but not for your 2g. This means 2g call performance will not change. It also means your 2g unlocks will still be possible. For 3g, expect this to render your SIM adapters useless and updating will probably prevent a future unlock from being possible.

• Enhancements to Maps
  • Google Street View
  • Public transit and walking directions
  • Display address of dropped pins
  • Share location via email
• Decrease in call setup failures and dropped calls
• Home button used to bring you to first page of apps on springboard. (Quickgold works still, but you get returned to first page if you have multiple pages at same time).
• Enhancements to Mail
  • Resolved isolated issues with scheduled fetching of email.
  • Improved formatting of wide HTML email
• Podcasts are now available for download in iTunes application (over Wi-Fi and cellular network)
• Improved stability and performance of Safari
• Improved sound quality of Visual Voicemail messages
• Pressing Home button from any Home screen displays the first Home screen
• Preference to turn on/off auto-correction in Keyboard Settings

As soon as it is available, I will post a working jailbreak guide and download link so stay tuned.