I have done B.Tech in Computer Science, and Masters in Humanities (specialization in Ontology). Can you kindly suggest me some places where I can do a Ph.D which combines both these fields?

I don't know what you mean by "ontology", which can refer to either the branch of philosophy (metaphysics) that is concerned with existence or the branch of artificial intelligence that is concerned with knowledge representation techniques for organizing information (both of those characterizations are very, very rough, of course). In the latter case, you might want to look into doctoral programs in either philosophy or computer science departments where there are researchers specializing in that, such as the (SUNY) Buffalo Center for Ontological Research (disclaimer: that's my institution!). For more information on this kind of ontology, see http://aitopics.net/Ontologies

Read another response by William Rapaport
Read another response about Education