Can I use PS3 controllers on a PS2

Is there a way to use a Playstation 3 controller with a Playstation 2? (Perhaps with a wireless dongle plugged into the front of the PS2..)

Our PS2 controllers are getting knackered, and I'm loathed to replace them if there is a way to use our PS3 controllers instead.

Unless Sony made the controllers send the same signals and have the same connectors there's no way that a PS2 can talk to a device created in the future without some intermediate hardware (as you suggest). However, it's not really in Sony's interest to do this themselves.

Wiki Answers and Answer Bag would appear to agree with me.

Though you're not the only one suggesting this. Though I don't see any answers that suggest how it might be done. Some sort of device like the USB to PS/2 converter you can get for PC mice and keyboards is what you need.