I already have an installation using .alx/.cod files that we use to install our Blackberry application via Desktop Manager, and also an "over the air" install version consisting of a .jad file and .cod files (uncompressed and no larger that 64K as specified by the mime type) that is downloaded from our website.

What format should I upload the application to App World as? 

I gather all the files should be in a zip file but apart from that I'm struggling to find much more information on the RIM website