I have done a setup for automation deployment using team-city and octopus. it is successfully deploying to required servers but I need to load balance as well. Any idea how can I combine them together. Or any other best option for performing load balancing with octopus.
Octopus can tie into your load balancing solution, but it will not perform load balancing.
Most enterprise applications use a hardware network load balancing appliance. For example F5's Big-IP product line. You can also create a software solution like John Hoerr suggested.
Once you have a solution in place you can then script Octopus to automate configuring your load balancer in a way that meets you business needs.