My iPhoto saga has ended happily with a working shared. I used an access control list method I found through Google.
I can use almost all the iPhoto features as either user. One strange thing is that I can't delete a photo as myself - but jen (whose account created the library) can. Whatever, I find it acceptable that I can read/write the files as myself. All this so that when I use the mac, once in a while, I can use iMovie and access the family's photos from there.
Next up - Quicken 2007 for mac.
Update 9/11/2008 - I can delete files. Hmmm, not sure why I could not before.