They give their files strange names. I change them to something.pdf or something.gif when I'm downloading.
Of course you can do all three. Your PostScript dial will be at http://members.tripod.com/~axum/cgi-bin/combo.ps until the next sundial maker comes along and writes over it.
These sites will convert your PostScript, etc., to other file types.
Remember there are plenty more sundials you can make at the You Can Make a Sundial! page.