I can imagine companies like Apple losing the iphone and returning to being mobile  service providers ( itunes) and the Visa / Amex /Banks becoming the next generation of mobile handset makers…as security becomes an issue ( phone as wallet).

The advantages of having all your money at your fingertips in real-time by mobile should have some interesting spin-offs.
How are business transactions going to tracked -taxed ..? Will the Tax Office inspect mobile phone transaction.
The disappearance of the cash ( black ) economy ?
A tipping point should surely come ..when coins and notes become too expensive to circulate as demand for them drops ( 10 -15 years ) 

I wonder if any country would dare to make records public ( increasing security by making all transactions tranaparent )  once cash had disappeared…casuing  tax receipts to increase.

Addendum: 16th June 2010

What if…as in Africa , the telecoms allow credits to be traded as money..do they become Bankers as well…able to create as much ‘credits’ as they like and control inflation as well.

Could be a regulatory mess …if we can all become monetary issuing entities.What would the consequences be?