While webkit browsers have native CSS support for text stroke, you'll have better cross-browser compatibility if you use the text-shadow style appropriately. The following CSS will add a 1px black stroke around the text. Note that this will only work on browsers that support the text-shadow property. But, as stated above, far more browsers support text-shadow than text stroke.
p { text-shadow: -1px -1px 0 #000, 1px -1px 0 #000, -1px 1px 0 #000, 1px 1px 0 #000; }