Next Tuesday, Google (GOOG) will unveil the much hyped HTC Dream, the first commercially available mobile phone shipped with Google's own open-source operating system, called Android. But this week, attendees at Google's Developers Day conference in London were given a sneak peek at the device.

Reactions have been mixed.

While an open-source OS on a mobile phone will invariably lead to exciting applications and features sometime in the future, the current version is underwhelming. Flaws include a clunky user interface and long load times, as seen during the Google Maps demonstration.

Of course, that isn't surprising: Apple's (AAPL) iPhone seems to have cornered the market on "sleek" and "streamlined" (at least if its ads are to be believed), and developers are going to have a difficult time keeping up with the Jobs's.

The phone itself was shown with a black design, a welcome change from leaked photos that made the device look like a hospital call button - presumably to appeal to that all-important over-65 demographic. Though it boasts an impressive 480 x 320 touchscreen, the overall size of the Dream has been described as "bulky" by industry insiders.

The flip-out keyboard -- regarded as the phone's poorest design choice -- wasn't shown in the demonstration.

Adding insult to injury, the Taiwan-based manufacturer HTC will be releasing the infinitely more elegant HTC Touch HD around the same time as the Dream. In looks, if nothing else, the Touch has a clear advantage.

On the plus side, the phone is equipped with an accelerometer which, like the iPhone's, will sense movement and can incorporate it into applications.

The phone does have another major handicap: It lacks Bluetooth API. Although Bluetooth headsets will be supported, any application that would require Bluetooth will have to be put on hold.

For how long, you ask? Not until the next Android version is released, which isn't in the foreseeable future.

Rumors of an "iPhone-killer" have been quelled for the time being. But after the phone is released and the Android software passed around among developers, we may see improvements in the interface.

At that point, Apple may get a little competition.