I had the Epson Perfection 4490. It gives good quality scans for both slides and negatives, and can be picked up for less that $150 in a lot of places these days. I actually just packaged mine back up to pass on to a friend in need of a scanner.

The actual scanning is easy enough--push a button on the scanner, approve the settings in the software, and wait. It's the rest of the process that is tedious. This is really just a limitation of consumer level technology. You can only scan a few items at a time, and they must all be placed in the carrier by hand.

If she just wants all of her slides in digital format, but doesn't necessarily need or want a scanner for anything else, it might be a better investment to look at scanning services. There are various places online that do it through a mail-in service, and a look in your phone book should turn up some local resources. (I know that chains like Ritz, Wolf, etc. will do bulk scanning for pretty reasonable prices.)