You may also change your title to "To all Blackberry Users and non-users" to catch attention. Anyway, you can create a content with some images about the application - it's use and how will it make a difference on users' experience. You can also make comparisons from other applications to see blackberry's advantage over the others. Simple yet helpful information will sell the application.
I would highly recommend hiring a dedicated copywriter. Any substitute for powerful copy will produce limited results if any. I wouldn't settle for anything less than skillfully written copy that speaks directly to your audience and presents the benefits of your app in a snappy, concise manner.
Linear Mode
Forum Contains New Posts 
Forum Contains No New Posts 
Forum is Closed