Famitsu has precious few (well, precious two) screens of DS de Yomu Tezuka Osamu Hi no Tori, the DS adaptation of Tezuka's Phoenix manga, but there's enough information there for us to get an idea of the presentation, at least. Basically, the full page appears on the bottom screen, and one panel at a time is zoomed in on the top screen. It's a very similar approach to Marvel Digital Comics' Smart Panels viewing style. We just hope that, unlike with Smart Panels, you are also able to move the panel view around manually in order to see more than just the focal point of each panel.
The 12 volumes of Phoenix are being divided into three DS cartridges, each retailing for 4,179 yen ($37). $37 isn't terrible for four books' worth of manga, but collecting whole series in DS format could still become painful quickly.