Here are the official sales information from the PlayStation Meeting 2005:
5.07 million PSPs sold worldwide
2.74 million PSPs sold in USA
2.33 million PSPs sold in Japan & Asia
11.2 million PSP games sold worldwide
7.3 million PSP games sold in USA
3.9 million PSP games sold in Japan & Asia
Just 48 games have been released so far for PSP
150 PSP games will be available by 31 March, 2006
4.3 million UMD movies sold in USA (Including 1 million Spiderman UMD Promo)
Just 400,000 UMD movies sold in Japan & Asia