Which "POC Client", exactly? There are many different versions of POC; Nokia's versions, Orange's "Talk Now" version (by Kodiak), Motorola's version (not on any phone yet, as far as I know).
And what do you mean when you say "for EPOC"? For the emulator on a PC/Windows? For Series 60? For Series 80? For UIQ?
In any case, some Series 60 phones from Nokia have it built-in. I don't know if a user-installable .sis package has been released/published.
And the POC version to use depends on what your local operators support (if any), because without an operator service the client is useless.
OK, so you'd want a POC client that works with the SDK emulator. I don't think there is one (I think only versions compiled for the target device are made available & the emulators in the SDK needs versions specifically compiled for the emulator - and different versions for emulators compiled with different Windows compilers at that; CodeWarrior, Microsoft/Borland).