here's some quick notes on using the parallax hitachi h48c 3 axis accelerometer module using the usb based BS1 (or i suppose any bs1) and the debug stream.
my project was to add an accelerometer as a periperal attachment to a linux system.. one of a few sensors i was using for instrumentation.. one the the things required was a way of using the bs1 usb module under linux/unix (and yes.. i have code!) heres a photo or two of the module i built:

accel.bs1 here is the BS1 code to read the sensor as fast as i could possible try.. i suppose theres one more tweak i could try, but its likely the benefits would be marginal. i stole the spi routine from the parallax example
acceld.c heres the c code i use under linux to read the sensor
bs1debug.c heres an example bs1 debug stream parser, accel.c was based on this
notes:

the bs1 on-board ftdi usb to serial converter is supported just fine under linux it might not seem obvious how things work by the code example, and the lack of documentation.. but

whenever you send a "debug" message the basic stamp sends a copy of all the ram contents via the debug stream, thats pretty much it, no matter how much you want 'DEBUG "hello world"' to work in your linux program, it wont... sorry..

the stream of data coming from the BS1 consists of "debug" packets and "connect" packets. as of yet these are the only packets i know of, and the palendrome-like nature of the bitmasks suggest it may be the only two..

i do not know how to disable "connect" packets

i do not know how to utilize a connect packet to reset the device... yet

these are doodles!.. just to prove i could get the thing up and running, and is vulnerable to a buffer overflow.. because i didnt bother to put in the check if i ran out of buffer space... you have.. what i have.. when it worked :)