The only file size info I could find on the D60 was a chart on
Dpreview.com
According to the chart, the average file size of a JPG at the highest resolution, in fine mode, is about 3,400kb, so a 1gb card would hold about 290 shots.
Size of a RAW image, according to the chart, is 9,100kb, so a 1gb card would hold about 109 shots.
These numbers are rough estimations; the size of a JPG file changes according to the content of the image, so the actual number of shots a card will hold varies greatly depending on what you're taking pics of. I've never shot in raw myself, but I believe that RAW files are always the same size because they are uncompressed - is that correct?
Anyway, Binkrin - get more cards! No matter where you go or what you shoot, having only one memory card for your digital camera is not a good thing; you whouls have at least one backup that's equal in size to your primary card, and I like having several backups. My primaries are 1gb each, and I have several 512mb backups.
It's also good to split your pics up when you're on vacation at a place like WDW so that if you lose a card - or your camera - you don't lose more than one day's pics. If you don't have a laptop or some other portable storage device to download the pics from your cards, you should have at lease one card per day of your trip, plus a backup or two. After each day, take used cards out of your camera and leave them in your room safe, and carry only empty cards with you in the parks.