if 1gb is all you're after, there are a couple different usb memory drives that are offered in that size. they won't be very cheap, though. i'll see if i can find a couple.
the bad thing about jumpy's idea is that you would have a large, heavier thing to transport, as well as a power adapter to plug in. if you find a memory drive, it will be the size of a large key, way more durable, and won't need any extra equipment. but, again, more expensive.
if you just want it to store images from your digital camera, just get a camera that uses removable flash memory. for instance, my olympus d-230 uses smartmedia cards. their about $30 a pop at 128mb each. other types of flash media come as big as 512mb or more. get a camera that uses the type you want.