Hi all,
there's a company in the UK that sells a lot of stuff for car builders, on page 25 of their catalogue (
http://www.carbuildersolutions.co.uk/download/cataloguejuly2005.pdf ) there's a "legends sheet" with lots of words and symbols printed in white on transparent film... I don't have any personal experience with that but this is the way I planned to do it... at least as long as Mark won't explain me what screen-printing is ;-)))
I've dealt with CBS and found them to be great to deal with. Nice products at fair prices. Regarding screen-printing (since you didn't ask... ;-) ), here is a link that will help explain it better than I could.
Screen-printing - Wikipedia, the free encyclopedia
Cheers,