CRUMp
A probabilistic prediction system of protein phosphorylation sites
...The sequence headers list the accession number of the protein sequence and the position numbers of known phosphorylation sites. Note that CRUMp may predict additional phosphorylation sites that have not been experimentally verified yet.
The testing dataset is from Biswas et al. 2010, http://www.biomedcentral.com/1471-2105/11/273/additional.