So I spent all day trying to figure this out. The internet claimed that my Galaxy S Vibrant (Model #: SGH-T959ZKBTMB Carrier:T-Mobile) should be able to update to 2.2 firmware, but kies refused to let me even connect my phone and gave me that "Your model is not supported,bla bla" junk, where as the internet told me that kies should work. Then, I tried using Samsung New PC Studio to update which told me that my device wasn't registered. Then I struggled for hours as to what that meant. Then I found Samsung
and I made an account and registered my phone and what not and it told me that I needed to use 'Samsung Kies mini' which is
compatible with my model and it updated my phone on the first try. I hope this helps!