Im sure we posted about this before but gizmodo have new details on the 8GB Mem Stick heading to PSP.
Sony announced it's raising the capacity of its Memory Stick Pro Duo to 8GB. Going on sale in Japan on March 9 for $325, the eight-gig flash memory cards won't work with all Sony VAIO laptops or Cybershot cameras—only with those sold in 2007. The good news is that your PlayStation Portable (PSP) will accept the new flash cards, but you'll need to be running firmware version 2.81.
Of course, Sony has such a proprietary mindset that some of its products aren't compatible with its own proprietary memory sticks. You might want to check the compatibility page (which doesn't include the 8GB Memory Stick yet, but promises to do so soon), listing the dozens of Sony products and telling you which one of the company's Memory Sticks will work with each. It's like navigating through a maze. Not amazing at all.