Upgrade to the newest firmware on both PS3s and there will be a new utility in the settings that will allow you to copy all of your files from one PS3 to the other using an ethernet cable (you can even transfer copy protected files and game saves that don't normally allow copying).
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You cannot just remove a hard drive from one PS3 and put it in another and expect all information to transfer over. You will have to format the drive.
Upgrade to the newest firmware on both PS3s and there will be a new utility in the settings that will allow you to copy all of your files from one PS3 to the other using an ethernet cable (you can even transfer copy protected files and game saves that don't normally allow copying).