Hmm, is there a vB4 mobile style coming soon? That would be the ideal of course.
I just want something my members can use on their phones that makes it easy to check and reply to threads etc.
Internet Brands is taking a two-prong approach in regards to mobile devices. They are working on both a dedicated per-device app and also a mobile style. Currently an iPhone app is close to being ready while the mobile style is still in development.
You can find some screen shots of the in-development mobile style here while more information about the iPhone app can be found here.