I am using the OKIPage 12i/n with OS X on my small local network and all works fine. The printer is connected to a wireless router with an ethernet cable, and my macbook pro can print via wireless connection. What I had to do is figure out the ip adress of the printer which I did with pinging to all addresses. There are tools to automatically ping a whole range of addresses (dont have their names at hand now, but just do a search at versiontracker) and that should return you the ip adress of the printer. Before that, you should make a status print-out at the okipage printer to give you the communication settings. (again, look in the manual for which keys to press) It might be that you have to change settings in your router. If I remember correctly, my okipage expected to be in a network configured for something like 192.168.0.1, but my router was set for 192.168.1.1. So I had to change that in the router settings.
After you have set those things to correspond, and know your ip adress, it is simple with ip-printing, entering the ip nr. and loading the printer description manually (I used the one, that I used to use back from the days of os9)
should work, at least does with mine.