Yeah, i've tried Iloveim, it pops up with a little messege saying like something isnt supported by the wii, then it loggs you on. You cant scroll down on your friends list though and you cant send messeges because I guess the wii has a popup blocker XD
meebo works for me but its not great but its wii you no.
im version 3.4 firmware in usa.
meebo worked fine for me.
by the way i thought if u plug a usb keyboard in the back of the it would work. but i havent tried