We're not a commercial source but the Drosophila RNAi Screening Center does offer some libraries for off-site (meaning, in your lab) screening. In addition to our on-site screening with full genome- or sub-libraries. The sub-libraries include a kinase & phosphatase set. You can check us out at http://www.flyrnai.org. Also, we can build a custom sub-library from a gene list.