The first handsets powered by Microsoft's Windows Phone 7 OS are set to become available for purchase on the market sometime in late 2010, most probably in the fourth quarter of the year, yet we can already have a look at some of the prototypes that handset makers are working on. Three such phones were spotted at the MIX10 conference on Monday, and some photos with them are available now for your viewing pleasure.

Among these devices, which have been brought to light by the guys over at Engadget, we can count the Asus prototype that was used for the showcasing of Windows Phone 7 back at the Mobile World Congress in Barcelona, as well as the LG slider that emerged a few weeks ago. In addition, we can also have a look at a Windows Phone 7 Series device from Samsung, which comes with an OLED screen, as well as at an Acer handset, put on display at the MIX10 conference.

There are not too many details available on these handsets, but it seems that we should expect for a minimum of 256MB of RAM and 8GB of flash to be included in the package, as well as for DirectX9 acceleration to be there. At the same time, one can also make assumptions on what these phones will include based on the hardware specs Microsoft already unveiled for the Windows Phone 7 Series devices.

According to the guys over at slashgear, “in the sensors department, all the phones must have a-GPS, Accelerometer, Compass, Light, and Proximity. The cameras need to be at least 5MP, have a flash, and a hardware camera button. […] the CPU needs to be a ARMv7 Cortex/Scorpion or better. Screens need to be at least HVGA, and have a resolution of 480×320.”

These hardware specifications are mixed with the requirements for the exterior buttons, which include the presence of only three hardware keys on the front of the phone: Back, Start, and Search. However, additional buttons will also be there, including camera keys, volume keys and other, only that they will be on the side of the device. Until more details on these handsets emerge, you can have a look at them in the photos attached to this article, as well as on the video below.