What, so it's only available for PS3 controllers?
Oh well. I'll wait. :l
The easiest and most supported way to connect devices to phones is through bluetooth. Both the Wii and PS3 use bluetooth to connect to their controllers, meaning you can do the same with phones. To be blunt, the Wiimote is a poor non-motion controller and the PS3 controller is a far better device to work with. If you really wanted to, you could make your own clip for a Wiimote. There are plenty of tutorials on Youtube showing how to connect both Wiimotes and PS3 controllers to phones.
Additionally, this should work with the iPhone if you've jailbroken it.