Does 'Open Telecom Platform' mean that there are devices I can actually use OTP on at this moment in time?
"Open telecom platform" is powerful set of erlang libraries which allow you to create fault tolerant systems easily. It's not an OS or device. It's something which runs anywhere erlang runs.
The "Telecom" refers to the fact that it was originally developed to support the software on Ericsson's telecommunications switches. So yes, for all you know, if you make a phone call, an Erlang-based switch may have routed your call.