Money Tansfer System via Mobile Phones

  The biggest hurdle to a physical money free society is small, personal payments.
  The easiest way to pay my friend £10 is to give him a £10 note. I could make a £10 PayPal transaction to him, but not if i am out, not at comp.
  But what if you could transfer money (like paypal) over your mobile phone?
  I could simply text a company the AMOUNT, your PIN, and the destination MOB NUMBER, and it would electronically transfer the requested amount to that persons bank account. It could send receipt txt to both people!
  what do you think?