Have you set up your Photoshop scratch disks properly and provided enough RAM/memory for the app?
I don't know about PS3, but in my old Photoshop version, you go to Edit > Preferences and then make the required changes.
This is the only solution that occurs to me right now. Usually, Photoshop is a sturdy app and personally, I've never suffered crashes. Of course, I haven't tried the newer CS3 version[s].
All the best

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