You could try importing from
http://www.lik-sang.com/
They sell Japanese and American PSP's at good prices. Remember that you will need a plug adapter to change the plug from 2 prongs to 3 (normally a couple of pounds from an electrical retailer). Also note that while the PSP games are not region coded, eg they can be played on and console, the movies are region locked so I would suggest a Japanese console as its the same region as the UK (region2). I bought a Japanese one last year and it plays all the UK movies and games fine - plus you can set the language on the system to English by default.
If you really want to impress, then why not go for the limited edition white PSP's only sold in Japan.
As to games, I tend to buy mine from
http://www.dvdboxoffice.com free shipping and much cheaper then buying in the shops over here.