I met the founder and CEO of GoPhoto.com at Photoshop World a few months ago and decided to give their scanning service a try with my grandfather's and father's Rollie negatives from 1930-2000.
Their unique service has no up front cost - they scan and you only pay for the images you want to keep after reviewing them online. They return all the originals. Any format is supported and the scanning is done in the USA. 2000 dpi is standard, 4000 dpi is only 25 cents more per image. 35mm is 37 cents per image, medium format is 99 cents.
They scanned over 11,000 negatives for me and did a fabulous job, removing dust and scratches on all. I got the scans back on DVD.
I give them a 10 out of 10 for their wonderful service.
(No, I am not paid by them for this endorsement, but I can send you a discount coupon if you like and I get a discount too! PM me with your email and I will send you the coupon)