Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
SD or DDR vs. DDR2. No can do, plus it won't physically fit. DDR2 is cheap, anyway - go buy yourself a 2GB kit of DDR2-667MHz.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.