We study the problem of reaching a consensus in the values of a distributed system of agents with time-varying connectivity in the presence of delays. We consider a widely studied consensus algorithm, in which every agent forms a weighted average of its own value with the values received from its neighboring agents. We study an asynchronous operation of this algorithm using delayed agent values. Our focus is on establishing convergence rate results for this algorithm. In particular, for general network topologies, we provide a bound on the time required to reach consensus, which is an explicit function of the system parameters including the delay bound and the bound on agents' intercommunication intervals.