Did a little looking around, because I did not recognize the extension. Looks like it's an archive for WebEX.
WebEX for iPad is your best bet. You might want to visit the support site first to see if it will download and view the files. The description on the apps' App Store page is a bit vague on the point.
The other option is to convert the file to a .wmv. I'm not what sure what tool you'd use for that, but it would probably have to be on a computer. After you have the .wmv you should be able to use anyone of several apps to view it. I use OPlayer.