Basically, you can create AppUp ..er.. apps as native Windows exe (*.msi), MeeGo applications, Java programs or encapsulated WebApps (JS/HTML5). The first three need integration of their SDK for authentification purposes. With the WebApps and the encapsulator mentioned above, things are more comfortable (test on local browser, then wrap online, check embedded in wrapper, then sign and submit). Btw., for the future, they seem to be heading for WebApps as main target.
All submitted programs must be signed, so you need a certificate (can be requested from the Intel site and is free for one year). Upon completion of their approval process, you get a nice little report 😉