A few years back, I spent a not inconsiderable amount of time scanning in all our photos, plus all the photos and slides from my parent's house. I bought a second hand slide scanner and a second hand flatbed scanner from eBay. When I'd finished with them, they went back there for sale. I did the scanning over the winter so it gave me something to do on the dark nights.
There are companies which will do it but you then have to trust the postal service and the company to not lose your material, plus if you're paying for each slide to be converted, you'll have to check them all individually to make sure they're not photos of anyone's feet!
From memory, it was a Plustek slide scanner.
Sent through the ether by diddling with radio waves