Don't get those, I've heard now 3 people (including myself) not liking those modules.
If you can, look at anything but corsair, well except for the Dominator 1066 and 1111 RAM. Something like: Crucial, G.Skill, Geil, Kingston, Mushkin, OCZ, Patriot and SuperTalent. All of those but in DDR2 800.
The only XMS2 that seems to be a decent kit is the XMS2 DDR2 675, so that one should be the only kit from Corsair I'd recommend.