The Ultra-D uses plain old DDR RAM, not DDR2. Back to the drawing board for Dwayne.
Getting 2GB of RAM isn't a bad idea, but unless you are overclocking a lot, you won't realy see a performance increase after switching to G.Skill from Corsair. And even then, Corsair isn't all that shabby at overclocking.
AMD64 X2 4400+
DFI Lanparty Ultra-D
2GB Kingston Hyper-X (2-3-2-6)
TT Big Typhoon
eVGA 7900GT KO Superclocked (650/1650)
250GB Maxtor DiamondMax SATA2 HDD
Hiper Type-R 580W SLi PSU
19" Sony Trinitron CRT