What is the most recent/effective way to hack and get backups working on a ps3?

Well, as the topic says, what's a good way to get a ps3 hacked? The firmware is 4.25 and I'm willing to downgrade if need be.
Also, I have no external hdd so is it possible to use the ps3's internal memory similar to a psp? If not, I have some dvds that should work.
If you need any more info, please ask and thanks in advance.

wait. The LV0 private key has been leaked, its only a matter of time before a signing tool appears allowing backups to be signed and played as if they were originals.

Alright, thanks. I'll keep an eye out for that.