Like something from a certain shop chain's adverts, the latest raft of PSP's aren't available in mere silver, red, and white, but rather in mystic silver, radiant red and pearl white. I'm sure you can see the subtle difference. Presumably this is our equivalent of Asia's Carnival Colours PSPs.
The white and silver systems are being made available this month, with the red system coming in March. That seems to neatly put down my theory that there was a Valentine's Day tie-in, although white, stereotypically speaking, a pretty girly colour so you never know. Maybe Sony expects to get a tonne of orders in the next few days.
Pricing is exactly the same as every other PSP colour variation, starting at £130 and varying depending on the specific bundle. If you're of the persuasion whereby a silver, white or red PSP will sway you towards purchasing a console now, despite having held off for the last few years then you know what to do.