As of May 24, Amazon Web Services added the ability to add Elastic LoadBalancers (ELB) to security group rules. This will allow you to get more specific with services that are load balanced in your security groups, instead of having to add a rule accepting inbound traffic from everyone (0.0.0.0/0). While this is a big step, ELBs themselves do not use security groups to determine who can access whatever port they’re forwarding, so if someone knows the public IP of the ELB, they can still reach the underlying ports on the EC2 instances being load balances.

But this is a good step, we look forward to seeing more development.

Source: Amazon Web Services Blog