I just purchased some AC to USB adapters from Monoprice for my iPhone 4. They work fine on charging my PRS-650. The description is “High-Speed WALL Power to USB Female Converter (1000mA) – Black” The item number is 6767. While they are kind of cheap feeling, at USD $2.16 each they are ok.
Item number 6767
Input: AC 100-240 V, 50/60Hz
Output: DC 5V +/-5%, 1A max, 150 ma min.
http://www.monoprice.com/products/pr...seq=1&format=2
They also have cables for ~ USD 1.00 each. I already had the cables so did not purchase from them.
http://www.monoprice.com/products/su...&cs_id=1030307