It appears that rumours are floating around on various message boards of a MySims game in the works for PC.  I don’t have nothing to back this up, but apparently it is described as the following:

“Explore a whole new world with MySims™ for the PC—it’s a world you can transform and share with your friends! With a little creativity and some help from the locals, you can make this place thrive. Discover what the residents want and need so that you can help them enjoy life in their town. Design a hot tub or a jukebox from scratch, build homes and businesses from the roof to the front door. Each of your creations is unique. In MySims for the PC, you can now chat and play games with your friends online as well as share your creations with them through email and IM. New residents, buildings and areas are unlockable as an added bonus! And Finally, Power Users can take advantage of the graphic power of the PC by running the game in beautiful high-resolutions all the way up to 1600×1200!”

After a google search, GameSpot is reporting it to be true.  No exact date is known at this time, but it would be cool if it came out around October with the release of MySims Kingdom.