An online protein interaction server has been designed and implemented to make predictions for 256 nonhomologous protein-protein interaction sites using patch analysis. Predictions of interactions sites are made using a scoring function that ranks four parameters, Solvation Potential, Hydrophobicity, Accessible Surface Area and Residue Interface Propensity, for overlapping patches of surface residues. Using the server, correct predictions were made for 85% of an original hand curated data set of 28 homodimers and for 65% of a new dataset of 256 homodimeric proteins. This is an increased prediction rate over the original algorithm, and proves that the method is valid for a larger set of proteins that includes more diverse interaction sites. In addition, a number of proteins for which predictions are categorized as incorrect, are shown to have alternative protein interaction sites on their surfaces.