The Feynman Diagrams has anti-particles as particles that travel backwards through time, with the same properties as thier 'normal' counterparts.

The matter/anti-matter relation is such that when they get together they annihilate each other in a flash of energy. Thus I would be led to believe that anti-time is some how the arch nemesis of time in that they too would annihilate each other when they met. However time is not a particle, just like space isn't. So talking about anti-time is like talking about anti-space, I don't think that either of these things exist even as mathematical 'tools'.