not sure it can be "any" IP platform, but most large manufacturers like Avaya, Cisco, Nortel, Miccosoft are partners with Polycom. Obviosuly the Polycom analog solutions will work most anywhere and most standards based IP endpoints can register with an IP PBX.
I've got Tandberg video devices on my desk here, T150 and 1000MXP, registering (and working without video) to my Avaya IP Office LAB system and also, if allowed, with the Cisco CM sitting behind that system.