If you want to scan negatives, then I highly recommend one of Nikon's film/negatives scanners. I am currently using the Coolscan V model to scan all of my collected slides and negatives. It does a fantastic job, albeit a little more slowly than Nikon's other (and more expensive) models. Although a little pricey, you can easily sell it on eBay once your scanning job is finished.
If you are only interested in scanning photos, then just about any inexpensive flat scanner will work. I use a Canon Lide50 that I bought new at Staples for $40, and it does a very good job.
I am using both of these scanners with a 4th gen 15" powerbook running 10.4.1, and everything seems to work well together.
Hope this info helps, and good luck on your project!