Slashgear says i-Mo is roughly the size of a small keychain fob, and also has a microSD slot for data storage. If you would rather have a direct connection between your device and the internet, you can also connect via mini USB cable (7.2mbps down/5.6mbps up). The 802.11b/g wi-fi can also be used to give internet access to other gadgets at the same time.
Price and release date are still unannounced, but I wouldn't mind seeing AT&T or T-Mobile offering this up with a data plan. [Slashgear]