Sierra Wireless just announced the smallest USB EV-DO modem available in the market today. The Sierra Wireless Compass 597 USB Modem boasts of a 3.1Mbps download and 1.8Mbps upload speeds with a microSD memory expansion slot and their TRU-Install automatic software installation.

This USB modem is compatible with both Mac and Windows but I am sure that Linux users will be able to make it work as well.

If you are looking for a HSxPA version, Sierra Wireless has the Compass 885 USB Modem. This critter provides up to 7.2Mbps of download speed and 2Mbps (upgradeable to 5.76) of upload.

Both EV-DO and HSUPA USB modems will be available in the second quarter of 2008. As for the price, we have to wait until the release.