Dell started shipping the Streak in August. It is smaller than most tablets, with a 5-inch screen, and larger than a smartphone, though it has smartphone features so users can make calls. But it shipped with Android 1.6, which was considered outdated even when the device first shipped.

The initial updates of Android 2.2, which is code-named Froyo, will be pushed over the air to Streak owners who have unlocked units, .

Dell said unlocked units are popular outside the U.S. and that the OS would be pushed out gradually over the coming weeks. An update icon on the notification bar will inform users about the availability of the new OS.

The Android 2.2 upgrades for units locked to carriers will be pushed "later in December," Dell said. Dell is working with wireless carriers to ensure smooth rollout of the upgrades.

The OS builds in new features including support for Flash 10.1 and new applications such as a native Twitter client, Skype and Firefox. It also brings in "enhanced Microsoft Exchange support," the company said.