T-Mobile to fling Froyo at Samsung Galaxy S guys
Update coming this month
Curiously, it's not being delivered over the air, but rather through the Kies application Samsung ships with its handsets. That means you'll need a Windows PC on which to install Kies, download the update and transfer the new firmware to the phone.
And T-Mobile has confirmed that the update will only be made available through Kies - which makes us wonder if the OS is coming from Samsung  itself rather than the operator. If is is, there's nothing on Samsung's support site yet. ®