Retrieving and composing individuals' capabilities are the matter of several research fields, like competence-based management, human resources management, enterprise knowledge management systems, knowledge representation systems, etc. This work focuses on capability representation, discovery and composition in heterogeneous, and possibly distributed, knowledge representation environments. We define a capability representation language in Description Logics, and we propose approaches and algorithms for capability management and discovery. In addition, we outline how our proposals are implemented in a mediator-based prototype system.