Yes, its quite easy actually. Download the theme studio and create a new theme (zen) and then grab one of the OS 6 icon packs from the theme developer forums (couple of free packs there). To replace the icons, just click the old icon and pick the new one. Then for the wallpaper youll see the background for the call screen and applications screen and just replace that with your wallpaper.
I'm not at my pc right now so I don't have a direct link. But just google blackberry theme studio and it should come up. Or search it on blackberry.com
Posted from my CrackBerry at wapforums.crackberry.com
Yup, that's the link. Played with this thing all night long. And I hate fonts part God I hate it ... Why can that stay default?! It changes to some ugly font