Speaking of one-stop CSS web apps, Jacob Bijani created his own for generating border-radius rules. Using border-radius can get tricky if all four corners are not the same, as Mozilla is the only browser that breaks the recommended spec.

Find this helpful tool at one of four domains: http://border-radius.com/, http://borderradius.com/, http://css-border-radius.com/ or http://cssborderradius.com/.