As Denny said, if your web servers host the exact same content you shouldn't need a rule for this. Just configure a pool that contains the two servers and a virtual server that points to the pool. You may need to enable Snat Automap on the VIP if the clients are on the same subnet as the web servers or if the web servers don't have the BIG-IP as their default gateway.
This load balancing configuration should be fairly simple to test. If you run into any issues where you think a rule might help, repost here.
If you have questions on configuring the pool or VIP, check the configuration guide for your version on AskF5.com or contact support. They should be able to help with non-rool related questions.
Thanks,
Aaron