I know a few folks use airfoil and wonder if you've had this problem and how you fixed it:
Airfoil used to work fine, but has now started "skipping" or jumping as though it's a bad FM signal even though the wireless connection is fine.
Admittedly as i type this it is behaving itself, but its the first time in months.
I've had a few upgrades (which should make it better right?!) and also installed Airport Base station agent on my pc to try and combat itunes playing one song and then "playing" the next silently.
we've got a netgear router, A.E and max 2 laptops on the netork so i can't imagine we are overloading the capacity or anything.
I don't think its the laptops (both do it) as i tried switching on the computer speakers again and it was fine.