For a long time, but without success, I tried to get my Wiimote to work as a volume control for my Powerbook G4. The problem with the free software Darwiinremote always was that mapping the volume keys to Wiimote doesn’t seem possible.
That problem is partially solved now. The free software PTHVolume lets you define any other shortcut which can then be mapped to Wiimote using Darwiinremote.
Still, it’s not perfect. PTHVolume misses a customisable shortcut for the option-shift-volume combination which under 10.5 Leopard controls the volume in smaller increments. And, but that’s only an aesthetic issue, you can’t hide the PTHVolume icon from the menu bar as you can do with the normal volume icon.