Thanks for the comment. Our intention is to make the iPhone/iPad app available for free. On the iPad, we may be able to keep the calendar interface. In fact, on the iPad – people can just use Safari to go to the main home page and use the regular web site.
The iPhone however, is too small to use our regular interface. Unfortunately we’ll need to consider a different interface to make it work, but it will still be calendar-based somehow. I envision something similar to the built-in calendar app, with the individual entry data showing the amounts.
We are really anxious to get to the development of this piece – its just a matter of time. :)