Depending on how many large format negs you have, you may find it cost effective to let someone like Coe Digital: click here scan them and put them on to CD for you.
I have used them in the past and found them very good.
I have an Epson 3170 Photo scanner which will scan negs and slides up to the old 620 size (8 on 120 film). I have also scanned a couple of 4 x 5 negs, which if positioned correctly only cuts off a small section. What size are the negs you want to scan. I would be willing to scan them for you if you would like to send them to me with a CD (providing they don't exceed 4 x 5). Contact me via the envelope first.