Here's the actual link to get the Staphylococcus aureus genome. Actually, this database (AureusDB) seems to be the definitive place for Staphylococcus genomes. It looks like there are actually a few at NCBI (and possibly elsewhere) that you can download, but it looks like there are all in AureusDB. On second look, the Broad Institute database looks very complete, as does the one from the Sanger Institute. You should check them all out.
I would like to add this link with reference sequences for many species: http://hgdownload.cse.ucsc.edu/downloads.html (because you do not specifically mention staphylococcus in the title) for other people.