Regarding the IR tranceiver, I gather you're talking about the AirLink project that CU Amiga magazine did ages ago?
They gave a blank PCB away with one issue, which you could use to build the IR tranceiver.
It was very simple and worked really well. Though I redesigned and improved it for what I was using it for, but that's another story :-)
There was free software for it called InfraRexx. It had an IR code editor/setup prog and an Arexx port which you could interface other programs to.
So with some Arexx scripting, in theory you could use any IR remote control to control Songplayer, or any program with an Arexx port.
You could also send codes as well, to control TVs, VCRs, CDTV, etc, etc.
If you want a copy of the software, send me an email.
Anthony.