This update is reportedly RC29 and improves battery life. t-mob USA are pushing it out to handsets until november 10th. Now as I'm not currently in the US and would like the best O.S possible to maximise features etc I found a microSD update method here:
"Aparently, a lot of people were tired of waiting. The update was scheduled to take place over the air over the period of a few weeks, as reported by official T-Mobile sources. But like any good tech savvy gadget head, someone got cranky and decided to figure out how to do it on their own, and here’s the deal.
Download the update from Google website: https://android.clie...4-RC19 RC28.zip (even though it says RC28, apparently it is in fact RC29)
Rename the file you just downloaded to update.zip
Copy the file update.zip to the root of your micro sd card.
Now turn off your phone and turn it back on while holding the home key.
When you see a triangle with a exclamation sign and a phone, slide open your keyboard and press ALT-L to display the menu and then ALT-S to start the update process.
Wait for the update to finish. If prompted, press Home + Back to restart your phone.
Wait a little bit more and done! "
Main thing to note is not to use the 1GB microSD bundled with the phone. And also check which version you are running first....which I will, as soon as I can use the thing properly....