If you're upgrading to a PS3 Slim, you don't have to leave your game saves on the old system. The PlayStation 3's internal hard drive, USB slots, and broad support for third-party hardware make it almost as easy to transfer data between two PS3s as two computers. Some files, like game add-ons and extra content, may be protected from transferring this way, but you can re-download them from the PlayStation Network at no charge.
Insert the USB flash drive into a USB slot on the PS3. The slots are located on the front left-hand side of the PS3.
Go to the "Game" section of the PS3 menu and open "Save Data Utility." The PS3 should list the game save data stored on its hard drive. Alternatively, you can open the "Game Data Utility" to view installed game data like downloaded add-ons.
Highlight the game data you want to transfer, press the "Triangle" button and select "Copy" from the menu that comes up on the right side of the screen. Select your USB flash drive as the location to copy it to.
Remove the USB drive when you have copied all the game data you want to transfer, and insert it in the PS3 you want to transfer the data to.
Highlight the USB flash drive under the "Game" column of the PS3, press "Triangle" and select "Display All."
Highlight the file you want to transfer, press "Triangle," then select "Copy." The PS3 should automatically copy the data to the appropriate folder on its hard drive.
You can only copy and transfer game data that is not protected by the publisher. Protected files will not have the "Copy" option in their menus.