You have a few more options than round robin DNS, which is the crudest and least desirable form of load balancing.
1. DNS-based load balancing from someone like UltraDNS (there may be others). The big advantage of this approach over round robin is that it will perform health checks on the servers in your load balancing pool and remove any that are down from the pool. The disadvantage is that you're still dealing with a DNS system and it's related problems (DNS caching, proxies causing uneven load distributions, etc). If a node goes down that had active connections, you can expect some users to receive errors using a DNS based method.
2. Software based load balancing. Windows Server includes load balancing functionality, though I haven't dabbled with it since Windows 2000. IIRC, you need to have your servers on the same subnet for it to work, so depending on the way your host has architected things that may or may not work for you. You may be able to get them to put all three machines on the same VLAN and subnet, in which case Microsoft's NLB may work for you (and it comes with Windows Server 2003 for free).
Otherwise you have a lot more options if you consider using a Linux server as the load balancer in front of your web servers, from pricey commercial apps like Zeus to open source apps like LinuxVirtualServer, UltraMonkey, etc.