Splinter:

(1) craigslist could be a good start (as mentioned) – there are probably other local classified ads and local directories you can get listed in – try doing a google search on “free classified michigan” (it is in michigan – no?)
(2) As far as the point brought up that scanners are inexpensive ($100) and kinko’s offers this service for cheap too. Although these facts are true, I don’t totally agree with the above posters. I think there still could be business potential for you – but you have to make sure to position your service as very unique from purchasing your own scanner of just going to kinko’s. List on your website prominently why your service is so much better than kinko’s or scanning yourself – is it because you have higher quality and will retouch up photos? is it because you specialize in large quantities (1000+)? Is it because you have years of experience in the best way to organize full photo albums into dvd’s?
Don’t just show why you are unique on your website – write articles on the difficulties of proper photo scan and possible solutions (of course showing how a service like yours is the best solution). Send these articles to local blog writers and local newspapers.
If you position yourself well enough, you could build yourself up as the expert in the field who people will turn to when they need your specialized scanning service.
Good luck!

youngboy:

pretty tough to do since scanners only cost $100 or less, so they just buy the scanners themselves and most people use digital cameras anymore anyway, so they don’t even need to scan pics.