The "Neo FreeRunner" touchscreen device will be fully modifiable and features integrated Wi-Fi, assisted-GPS, and Bluetooth capabilities. (click for larger image)

The iPhone 3G will undoubtedly be a hit this summer, but users turned off by Apple's walled-garden approach may want to take a look at OpenMoko's open-source Neo FreeRunner.

The FreeRunner is based on a GNU/Linux, and it will initially ship with basic software to make calls, send and receive SMS, and manage contacts. But the company is encouraging users to write and install their own applications. Software updates will add features to the phone over time, and the company said an August update will enable location-based services.

The open nature of the device even extends to hardware, as users can download the full CAD designs to produce unique phone cases, although this may be too costly for the individual tinkerer.

The smartphone is the company's first in the U.S. market, and it sports a 2.8-inch VGA touchscreen. It will come with built-in Wi-Fi, assisted-GPS, and two 3-axis motion sensors that can adjust the screen based on how it's being held. The company said developers will be able to fully utilize all these features to develop applications.

It will also have Bluetooth 2.0 capabilities, 256 MB of internal memory, and a microSD slot for expanded storage. The oval-shaped handset measures 4.8 by 2.4 by 0.7 inches, and weighs 6.5 ounces. The smartphone will support U.S. bands, but will only be available with EDGE networks for mobile Internet access.

The Neo FreeRunner will be on sale at OpenMoko's Web site Friday, and it will be sold unlocked for $399.