Minimum power supply for AMD Phenom II X6 1100T?

According to AMD's website it requires 125 watts
http://products.amd.com/en-us/DesktopCPUDetail.aspx?id=...

However its usually the graphics card that requires the most power. Usually for a single card, and a CPU a good 500w+ PSU is enough. This obviously depends on what graphics card you will be using though, if any at all.

Alternativly, check out this PSU calculator:
http://extreme.outervision.com/psucalculatorlite.jsp

Well at the lowest end for pretty much any build:
Antec EarthWatts 380D $39.99 at newegg atm.

It will power any CPU pretty much and up to 1 PCIe connector graphics card.

But yeah as said above generally it's good to go with a good PSU in the 500W range. So you won't be drawing out max power all the time.