When the iPhone first came out and everyone was raving about its user interface I had to agree with them, despite being a long-term Windows Mobile user. Of course, like all new user interfaces there are always going to be some learning points but on the whole there is a lot to be said for an interface that was solely developed for the use with a finger.
Take the following screenshot, which is actually of an iTouch but could easily be an iPhone, you can see that at the bottom of the screen shot is a set of rollers. These are used to set the date and time that an appointment is to start. By flicking your finger across the rollers you can wind the date/time forward/backward at different speeds depending on how quickly you move your finger.
The clear advantage of this interface over the traditional date/time pickers used by the new appointment dialog on Windows Mobile (see below). In fact the Windows Mobile interface is so bad (actually perhaps old is a better term of it) that you can't reasonably use it with a finger, you really do need to either use a stylus or if you've worked out how, the d-pad.
The current guidance from Microsoft for new Windows Mobile applications is to build for the smartphone (ie no-touch) with the assumption that this is the canonical set of the controls available for both platforms. Unfortunately this is probably the worst thing you can do for a usable touch interface. In my opinion if you want to build an awesome application for the Pocket PC (ie Windows Mobile 6 Classic or Professional - urge why do we still have such silly sku names!) you should be focused on a "touch first design".
Side note: My apologies for the rather poor photo of the iTouch. Of course Pocket PC Controller (used for the Windows Mobile screenshots) doesn't work with the iTouch and my HTC Touch Dual has a barely competent camera under low light conditions ;-)