I was thinking of upgrading this to 8GB RAM with 4x2gb Corsair Dominator DDR2 1066 Mhz,
would this require me to purchase a new PSU and would this mobo handle it due to the Chip now running 4 sticks instead of the usual 2?
I agree with Gary, DDR2, don't bother, in 2 years we'll be on DDR4.
HOWEVER, if you insist, whether or not you can use 8GB depends on your op system. The board supports up to 16GB, however, Windows XP for example, does not. 32 bit versions of Vista does not either. And no, you don't need a new PSU to upgrade RAM.