Looks like developers have taken advantage of the SDK that Sony Ericsson made available for its Xperia X1 Windows Mobile smartphone. This week, Sony Ericsson added two more panels to the X1's user interface: one for Facebook and another for Microsoft's Windows Live.The X1's main feature is the panel-based user interface that rests on top of Windows Mobile 6.1 Professional. (Let's just ignore the fact that this is yet another attempt by an OEM to cover up WinMo.)

The panels act as gateways to the phone's many different features. They are sort of windows (pardon the pun) to other screens and activities. Touch the panel you want to go to, and it takes you there. A number of panels were developed for the initial version of the phone. Recognizing that social networking has become a key use of smartphones, Sony Ericsson added two panels that connect to social networking services.

According to Sony Ericsson, the new Facebook application uses the unique interface of the X1 to deliver an intuitive version of the site, putting images of friends onto the phone's desktop (standby screen) and showing their latest status updates as each user touches their friends' images. As you touch to view different information, icons and links change to give you one-touch access to the information you are likely to use -- for example, touch the photo icon from your profile page to see your photos, from a friend's profile page touch the photo icon to see their photos. Very nice.

I am an avid user of Facebook, and have come to rely on my mobile phone to provide me with access to the social networking site. I am sure many others do, as well. This new panel gives Xperia users the same option and an experience that is geared toward their phone.

Sony Ericsson couldn't leave out partner Microsoft. The Windows Live panel uses existing Windows Live ID to sync contacts held in the X1's phonebook, and the panel will provide easy access to the Microsoft messenger interface, including Hotmail and Live Messenger. The panel also will give users access to the Windows Live Search function, which is tailored to mobile phones and can be voice activated and controlled. Sony Ericsson said that other Windows Live services will be incorporated into the panel throughout the year.

The Facebook and Windows Live panels are available for free download via the device's on-board downloader and from the Sony Ericsson Web site.