Battery-USB-charger, will it work?

     +-----in[REG]ut------ +5V - USB pin 1 (red cable)
    |        gnd
    |         |
6V ---        |
    -         |
    |         |       
    +-------- +---------- 0V - USB pin 4 (black cable)

(I hope the schematics looks OK now, dunno how the boards handle ASCII-art).
I'm using 4 AA-batteries to power an USB-device (such as charing iPod or keeping an USB-fan going). Will this work? I think so, but I'd love some comments before I go and buy the parts... $10, but still.
Thanks in advance