Roger,
I had a family member who did this, but to HAVE it done for you is really expensive, and do you really want what are probably the only copies of precious films to be sent off, or dropped off someplace?
It depends on how many you have, but what she did was to use a camcorder--one of those that records directly to DVD. she bought hers (I think around $350)...and used a tripod so it didn't move, and just recorded the film as it was showing. The quality was as good as the original fim (which aren't that great on 8mm anyway)...but the dvds turned out great.
If you have a lot, it might be worth buying a dvd camcorder, borrowing one if you can't buy one. I would suggest borrowing one, and doing one. If you are pleased with the way it turned out, then it would be worth it to buy one to finish your project.
There are companies that will do it for you, but I don't know of any around here.
Good luck.