Hi,
Your application is exactly what I need.
While I enjoy using the browser as much as possible, a separate app is very handy until tfl makes its website much more mobile-friendly (I can't stand the wap version of their site)

In addition to what you've done so far, it would be fantastic to be able to route trips in real time, as done by some android apps. For example, choosing departure and end stations and figuring out where to change line and how long it takes to get to destination.

I'm not a programmer myself, but would be more than happy to contribute in testing the app and possibly getting introduced to learning python too!