Just got it!
Hey i dont know if you were able to solve your problem but i was having the same issue as you, i wanted to dump my pics from the iPhone to my laptop...it worked for me when i unplugged the iphone from the computer, then plugged it back in and after you hear the little chime that plays when the computer recognizes a USB device was plugged in, pay attention to the little window that pops up giving you the option to copy pictures from device to computer... if you have iTunes setup to where it auto syncs when you dock the phone, just minimize iTunes when it comes up and youll see that little window im talking about. sometimes the window pops up behind iTunes so look for it...any questions email me and ill walk u thru it via AIM or yahoo msngr or whatever!
hope this helps, if you already got it taken care if, i just wanted to help