re service company for the digitizing: In the Washington, DC area, Video & Film Solutions is probably a good bet. They do transfers for the National Archives, so they have a lot of equipment and experience.
You may also discover that old tape decks are readily and inexpensively available, as long as you have an I/O solution such as the AJA device Tim specified.
The other part of archiving is logging, so that after the immense job of digitizing, you can actually access the relevant material. Ideally you’d obtain text descriptions and thumbnail images of each shot. As the librarians say, “a misfiled book is a lost book.” By its nature, motion imagery is much more difficult to catalog, access and scan than are stills or words.
This forum is a wealth of information on all aspects of the task.
Good luck!
Bob C