Is there some link between women who have the spark and women who can learn to channel and damane and suldam? I have feeling that there must be.

Damane are the women who have the spark, sul'dam are those who can learn to channel.

Incidentally how many books in are you?

Who me? I've read all the books, but only once; probably not enough to talk with any authority to all the people here. That's one of the reasons I mostly just read the post and hardly ever post myself. I love the books though.

Yea, the characters seem to find out about this issue in TGH, though it goes into more detail in TSR with Egeanin. Its as Majsju said.