On Tuesday, AT&T and Sierra Wireless introduced the USBConnect Mercury, a USB peripheral designed to connect to AT&T's High Speed Packet Access (HSPA) 3G data network. According to Macworld, the device is available for free to users who choose a two-year DataConnect plan of US$60 or more (after a mail-in rebate worth a US$100 AT&T promotion card).

The USBConnect Mercury requires a USB port and Mac OS X 10.4.11 to install and run. The unit ships with a copy of Sierra's Watcher software which allows it to connect to AT&T's 3G network. AT&T estimates typical downlink speeds of between 700 kilobits per second (Kbps) and 1.7 megabits per second (Mbps), and typical uplink speeds of between 500 Kbps and 1.2 Mbps. An integrated MicroSD flash media card slot lets you also use the interface for additional storage capacity.

The device works on HSPA, EDGE and GPRS networks allows for access in more than 150 countries as well as provides 3G network access in more than 60 countries.

If you've tried AT&T's 3G USB products or have a favorite 3G card of choice, let us know in the comments or forums.