http://majescogames.com/accessories/
Haven't seen the communicator, but I saw the wireless link last night. It purports to work as the 1st party wireless unit really should have -- wirelessly replacing link cables in every game, not just the ones specifically supporting the adapter.
Cheap too -- I think it was only $9.99. [edit: errr, as it says in big bold numerals at the top of the webpage]