There are multiple parts to an arcade stick, the part that determines the consoles you can use it for is the PCB (printed circuit board).
There are a few PCBs that support PS2 as well as PS3, most notably the MC Cthulhu (available at lizardlick)
While there are some arcade sticks that support PS2/3 out of the box (iirc the MC Cthulhu takes some assembly), they typically have poor parts, and some of the PCBs aren't desirable (the Mayflash arcade stick maps to analog stick, which isn't enabled by default).