I've been doing some proof of concept work dealing with supporting mobile devices.
Looking at http://mobile.msn.com/pocketpc/default.aspx gives a pretty good idea of how to scale UI for smaller devices and you can use the ASP.NET mobile controls or just stick to basic html elements.
I'm used to PocketPCs & SmartPhones but not BlackBerrys, which seem to be very popular in the city at the moment. (Why did Palm waste their lead, rebranding and selling it's name back to itself?!)
So how to view a website via a BlackBerry if you don't have a physical device? Well I headed to the development program on their website and after a free registration I downloaded the BlackBerry Device Simulator. This is a set of emulators for the range of different devices, which gives the screen, keyboard, trackwheel, phone keys and allows you to simulate wireless network conditions.
After install, you get a directory of .bat files which load the emulators complete which photo-realistic skins. But unfortunately I still couldn't navigate to a website using the built-in browser. For this I needed to download the BlackBerry JDE which includes Mobile Data Service (MDS) simulator.
Once you run this, it acts as a proxy and forwards web requests on behalf of the device, so I could then browse away.