Here's a picture of a prototype for the new TellyMate Kit that I'm working on : The TellyMate TTL. It's essentially a re-arrangement of the (probably to be discontinued) TellyMate Kit, but without the RS232 connector and translation circuitry.
Once I'm happy that the prototype's OK, I'll be getting some 'proper' boards made up.
It communicates natively using 5v TTL serial signals (8n1), hence it should be compatible with any device which uses this format (PIC, PIC-AXE, Arduino etc.). All the board needs is Gnd, 5v and Rx (TX is optional). It's up to the user how these are connected to their system.
For those with Arduinos (and don't fancy the Batsocks TellyMate Shield), the power and serial holes are arranged such that downwards-facing header pins (as in the photo) will allow the board to straddle an Arduino (albeit 90-degrees to the norm.).