I got today the Teensy, so i can jailbreak the PS3.
Teensy costs $18 and it only needs a USB port on PS3.
Download this firmware and the Teensy Loader (for Win 7/Vista or WinXP). Connect the Teensy on your PC. Windows will recognize Teensy and will install it.
Now open the hex file and press "auto". The program will write the hex on Teensy. When finish, you are ready.
Now copy manager.pkg in a Memory Stick (FAT32). Power of your PS3 and remove the power cord (or close the power button from the back of PS3, if you have a fat PS3).
Insert teensy on the 1st USB port. Now connect the power cord (or press the power button from the back) and when you see PS3's red light turning on, press Power and then RESET quickly, almost together. If you press them correctly, you will see Teensy's LED turning up, then turning off and in a few seconds it will turning on again. This means that the jailbreak is succeeded.
Now in the 2nd USB port put the USB flash and from PS3's menu, select "Install Package Files" and choose to install the backup manager.
When done, select the Backup manager and press "O" on the update screen and then "X".
Backup manager will list the games you have. In order to run any backup, you must have an original game in PS3. Select the game you want and Backup manager will exit and you see the PS3 menu again and a screen of the game you selected.