I believe Graham is right ... if I remember correctly (no I DON'T remember what I had for breakfast yesterday) the top number of the time signature tells how many beats in a measure, the bottom number tells what kind of note (half note, quarter note, etc.) gets one beat ...
t.
PS ... OF COURSE I remember what I had for breakfast yesterday ... since it was Sunday, in an Italian household that means fresh meatballs right out of the frying pan before they go into the sauce (gravy?!?
) ....
t.
PPS ... hope this thread doesn't stray OT (OFF topic) now ...
t.