Thanks Ebarnacle, I actually do RTM, routinely, but there was precious little about transferring bought ring tones from suppliers and nothing about creating one's own; I suspect RTFM will provide the same result.
I suspect that, when I stir myself sufficiently to learn how to create MP3 files from a field-recording (courtesy of the daughters' interests in music I can get access to a Zoom H4, which should do the trick), I shall then be in a good position to work out how to transfer such a file to the phone, providing I have the required cables. And, while you might be able to give good advice on such matters, I suspect you're north of the equator and on a different system. In rural Oz, GSM doesn't have a good reputation although it works OK in the major cities; where I am, even the (supposedly superior for rural coverage) CDMA system doesn't function and CDMA phones don't have the nice removeab;e SIM and memory cards that GSM phones use.
But I'm sure Barbara could use your advice and I'd find it interesting.