You can do almost everything on your cell phone, and soon it could even replace your wallet.

The so-called "wallet phones,” which let you buy things, check your bank accounts and credit cards, are already in use in Japan and South Korea.

Now eight of the ten biggest U.S. banks are starting to offer basic services like checking balances.

Some offer more features now, and more are to come as the phones become more popular.

Visa launched a pilot program last week that sends text alerts to cell phones just seconds after unusual purchases are made.

The services are handy, and free.