Google Wallet enables Nexus phone users with a Citi MasterCard to pay quickly at dozens of large retailers. Just tap your phone on a PayPass-enabled card reader to make purchases. (Google is negotiating to expand service to other cards.)
Zong allows you to make online purchases with just your phone and a PIN. The charges can be directed to a credit card or your wireless-carrier bill. (Free, all platforms)
PayPal Mobile “allows you to transfer money between phones with a simple tap.” Once phones bump, type in the transaction amount, and PayPal does the rest. (Free; iPhone, Android, BlackBerry)
Square is ideal for merchants without credit card machines. With a small attachment plugged into your phone’s headphone jack, you can swipe all major credit cards. (Free—including the plug-in; iOS and Android)
Source: Details
