PSICQUIC client is a built-in feature in Cytoscape 3 and you do not install any App to use PSICQUIC service. New, improved version is now available in Cytoscape 3.1.0 core distribution.
PSICQUIC is a standard web service protocol supported by major interaction data providers, including IntAct, BioGRID, STRING, etc. As of March 2014, 31 major interaction data providers support this standard and you can access all of those at once by this App.