You can link any payment method you want, including a checking account from any bank. Once you've done that, not only can you send money quickly to a friend, but you can also use over 75,000 other services, including telephone lines, invoices, videogames, and all kinds of shopping.
Basically, with Visa QIWI Wallet, you can use your Android smartphone as a credit card to pay for any service or product. Visa QIWI Wallet only works in a few countries, however, so it's possible that it will only work correctly in Russia.
Requires Android 4.1 or higher