All this nostalgia led me to root around for all kinds of stuff from my speccy days. There used to be a magazine called Input that basically taught programming for most of the micros of the day. If anyone's interested, I happened to come across a forum post that directed me to this page:
which has PDFs for all 48 editions of said mag. Probably not a great deal of use for programming on the Pi, but interesting reading all the same, IMO.
This goes along well with the "BBC BASIC for Windows" that another user pointed me toward.