Topo scanning services

I know that there are companies out there that can scan a 7.5 minute
quad and produce DEM, DLG, etc type information. Does anyone have any
phone numbers or addresses of these companies.

Also, I am aware that LT-Plus (?) does this. Is this program public domain?
If so, where can I get a copy?

Thanks,
Doug Dotson
dotson@tate.com