From PSP-Vault:
"One of the first things we PSP fans have to be excited about is the
upcoming GPS accessory. We've known about the possibility of a GPS
accessory ever since before the PSP was even released; Sony's first
public exhibition of the PSP showed several units equipped with a small
GPS unit that attached to the PSP's GPS port. Sony
reminded us that the accessory was on its way at the Playstation Business Meeting earlier this year. And just this past week, we
learned an official price and release date for the Japanese market: December 7th for 6,000 yen (~$51 USD).
So why should you, or anyone be excited about the GPS accessory? What
will it do for the PSP? Can I use it to navigate my way around town?
This article will answer those questions, and many more. For
those that don't know, GPS is an acronym for "Global Positioning
System." It was developed by the US Department of Defense, but today is
free for anyone to use. Satellites in orbit around the Earth broadcast
signals, and receivers pick up these signals. After doing some math
with the numbers received from the satellites, the receiver is able to
determine your position on the globe. If you're interested in more (or
want a more technical explanation), the
Wikipedia entry on GPS is extremely detailed."
Read the full text here...
Source: PSP-Vault