if it sounds like a pluckd spoke, it probably is the spokes...
since it's a new wheelset, i'd guess they weren't completely stress relieved before you got them on your bike
see sheldon @
http://sheldonbrown.com/wheelbuild.html -->
"Before a wheel is ready for the road it must be stress relieved, because the bend in the spoke has to accommodate itself to the shape of the hub flange and vice versa, and a similar process may go on where the nipple sits in the rim. Some wheelbuilders do this by flexing the whole wheel, others by grabbing the spokes in groups of 4 and squeezing them together. My preferred technique is to use a lever to bend the spokes around each other where they cross. My favorite lever for this is an old left crank:
This particular technique has the added advantage of bending the spokes neatly around each other at the crossing, so they run straight from the crossing in both directions. As you go around the wheel this way you will probably hear creaks and pinging sounds as the parts come into more intimate terms with each other.
After you do this, you will probably have to do some touch-up truing, then repeat the stressing process until it stops making noise and the wheel stops going out of true."