Extract them to your desktop and you end up with three files called httpbc-installer-3.001, httpbc-installer-3.002 and httpbc-installer-3.003. Open httpbc-installer-3.001 with your favorite ZIP tool and it should recognize httpbc-installer-3.002 and httpbc-installer-3.003 as additional parts. Depending on the tool in use, it will then extract httpbc-installer-3.jar or just httpbc-installer-3. If the extension is missing, simply add .jar and you should end up with a binding component you can install via OpenESB SE admin console.
Don't bother about OpenESB version numbering which has been hard to understand since I entered the arena in 2009. I think the BC I posted is a good compromize between being fairly up-to-date while still working. And it gives you time to wait for fixes to the latest revision. Of course you're advised to do thorough testing what ever you decide to do. ;-)