This was on ivillage, Blondie:
"The reason that no one has the same information for you is that there is a wide range of normal. "Most" women feel fetal movement (quickening) at 18 weeks if it is their first baby (i.e. 18 weeks from your last menstrual period -- LMP). Some multiparas (those who have already carried a child to term) feel movement earlier, simply because they know what it feels like. The normal range is 16 to 20 weeks (LMP). "
I think I felt it about 17 weeks. To me the first movements felt sort of like a ball rolling around or something tumbling. It's hard to explain, but when you feel it, you think, "aha, there it is". Gosh, that was a fun time.