Do check out this video with Deloitte's vice chairman, Eric Openshaw, and this infographic PDF about Deloitte's findings regarding the over-55 generation dominating the market for smartphones and inevitably the app market too. The facts discussed and this challenge topic are too closely related to be a coincidence.
An intriguing insight I picked up on was the recommendations to initiate "customer service programs" for first time users. This reminds me of the Apple Workshops held at Apple Stores (http://www.apple.com/retail/learn/), but can obviously be applied to a diverse range of companies, including banks! Who are they to offer a product like mobile banking and online services without live person help? What works in banks' favor is the fact that they already have establishments to hold learning workshops like these.
Additionally, as more and more 50+ users start acquiring smartphones, it could be useful to make a new category in app stores geared toward useful tools for 50+, such as their bank's app for finance, skype for family connection, etc...