It didn't take long for the "open source PSJailBreak" to make it's appearance. 12 days in fact.

The original PSJailbreak was being sold for $170, the cloned one (x3jailbreak) was selling for $30, and now you only need to pay $20 for a USB development board and copy over the software. Or if you wait a little longer you can just use your jailbroken iPhone, iPod, and even a TI-84 calculator or jailbreak your PS3. As mentioned before though, you'll see some significant drops in vendor prices (once they're allowed to start selling the original Jailbreak again.) =]

It only plays homebrew at the moment, and the "pirate feature" (ability to boot ISO files) is temporarily disabled.

Exophase has more details on the new open-source implementation called PSGroove. As mentioned though, right now a programmable USB flash chip is required (Teensy USB dev board) but other methods will be made available in the near future.