Are you having a problem finding 300D software/drivers for Vista 64? 
I have found an easy solution to this problem that I hope will be as usefull to others as it was to me.
In the menu set commincation to PTP. Then connect your 300D to your computer using the usb cable. Switch on the camera and Vista 64 will as if by magic install drivers for it.
The next time you connect your 300D you should get the autoplay window appear. Once you have opened up your pictures you can use properties to change the default picture veiwer/editor to the one you prefer to use. If autoplay does not open on it's own, just open my computer and your 300D will be listed as another drive. Just double it's icon and your in. I hope this will be usefull to some of you, it certainly was to me. 
