organizing photos

On our imac, my wife and i have two user names. We have tons of photos on the computer of our 3 children. The problem is, I would like to clean up some things on this computer, starting with the photos. Some photo's are in kodak easy share, some are in iphoto, and some on my name, some on her name.

So there's 2 things I'd like to do;

1. I'd like to get all these photos in one place, so they're not scattered all over.

2. Is there a way to make it so that my iphoto is identical to her iphoto? For example, when she imports photos on her name, I'd like them to be equally accessible on my user account. And that goes for editing, deleting, etc..

Thanks in advance, this is annoying the crap outta me.