For which version of controller? The older PS3 controllers (Six-Axis only) use a 10k POT design, but not like the ones in PS1/2 or 360 controllers, they're smaller, and in the newer PS3 controllers (Six-Axis and DS3) they use a Hall Effect sensor that's nothing at all like the 10k POT ones.
http://forums.xbox-s...howtopic=648322You'd have to get replacements from another controller AFAIK right now. I know Mouser has the stick (not the cap, just the stick) for the PS2 and 360 controllers, but the ones in the PS3 controllers I've yet to see and would imagine they're around the same price if not more expensive for the Hall Effect ones, as the ones for the 360/PS2 can range from $6 to $15 a pop, replacing the controller is almost the better way to go there unless you have some old controllers just sitting around to get them from.
Sent you a PM as well.