Title^ For example when you want to split traffic, you want more than 1 web hosting to accomodate server bandwidth or space. ???
In simple words load balancing means, using two or more servers, for same site, might be not clear to you, so the easiest way for you, is check with your hosting provider about it and get their help, load balancing setup might be costlier than a regular high end server, so if your requirement is really not too much, than I suggest simply going for one high confi server, instead of load balancing, because it will cost you for two or more server and setup fee and load balancer fee as well, so its usually not for small sites
Sorry, I was in a hurry. Aassociatehit has summed it up nicely. A load-balanced set-up (which is what you will need if planning to use 2 or more servers) is very expensive as proper load-balancers cost several thousand dollars (for a low-end one) to purchase. A clustered set-up (without load balancing) would be fine when you require extremely high uptime guarantees. In this instance your site would be available of 2 or more servers but only one would be operational at any point in time. If something happened to that web server another would take over automatically to maintain uptime. However, as per your post I suspect this is not your primary goal, your primary need is to spread bandwidth and traffic over more than one operational server at the same time - which requires load-balancing. For either of these options, speak to your host, but neither of them will be cheap. The suggestion that you simply look at a more powerful server is probably the best solution at this time until your sites generate enough income to justify the costs of other solutions.
clustering a web server will be the best solution. If you tell us what is the OS, we could maybe help you more. Thanks
A simple and basic way can be to use different NS to point to different IPs. I mean make NS1 point to IP A and NS2 to IP B. This would be sort of a round-robin method. Not very recommended but the easiest to set-up.