When I was at the Mid-Atlantic Regional Archives Conference, I spoke to a vendor who noted that "in the old days" they could rely on advertising in the phonebook as a way of connecting with possible customers. But now, they have to find alternate means. It is not because people don't use the phonebook, but because the phonebook doesn't use headings that describe some of our "new" high tech businesses. For example, there is not a heading that relates to digitization.
So how do you find a digitization vendor? Internet search engines are helpful. There are vendor lists on various web sites. And some vendors are part of AIIM.org, so you might find them through that organization. Asking others in your region might yield a few names. But there is no way of finding every digitization vendor.
I've compiled a list of vendors in New York State for several digitization planning projects. An updated list will be published soon and will be announced here when it's available. A list compiled in 2003 is available in a preliminary assessment report for the Northern New York Library Network.
If you are involved in a digitization project, you can help others locate vendors by placing information on your web site about the vendors you used and brief information on the work they did for you. Every little piece of information helps...and your mention might be all someone needs in order to find the perfect vendor for a project.