Take this as a rumour for now but our pals over at PSPIta have posted that youllbe able to use your PSP to Jailbreak the PS3, talk about a slap for Sony, heres the translated article:

Before the advent of 3:55 custom firmware for the PS3 owners the only way to change the console was to use the PS3 Jailbreak (or its clones) or a USB dongle which is made possible thanks to the code to run on non-certified PS3 Retail. This "Jailbreak" in following through the concerted efforts of many coders, was ported to other devices and made open-source ( PSGroove ). They talked for a long time even to a port on PSP but the work ended abruptly. Now, via his Twitter profile, developer Brandon Wilson announced that he was able to develop a homebrew capable PSP to make a dongle to all intents and purposes it will be possible to downgrade procedures (until 3:55 fw that turns out to be 'latest system software on which it is possible the procedure) and, with the PS3 firmware 3:41 and lower, to enable debug mode and then code execution is not certified.
Brandon Wilson said that the release is imminent. We will keep you updated when new.

Just ported PS3 downgrader / service mode jig to PSP. You can use it for <= FW3.55 stuff. I'm cleaning it up, etc.., Will release soon.