It's a story that isn't going away. 2007 World Champion Kimi Raikkonen is potentially returning to F1 next season to drive for Williams. If it happens, and Schumacher stays for another year, we'll have 6 champions on the grid, which I believe would be the highest ever.
However, I have to question why he wants to return to the sport. We have seen some brilliant drives from him, but too many times in 2008 and 2009 we saw a driver who seemingly had no desire left to remain in the sport. He could have partnered Lewis Hamilton at McLaren in 2010, but instead chose to make more money by leaving F1. He was the highest paid driver on the grid, money can't be in short supply for him. Quite why he is looking to join one of the backmarkers is a strange one.
His trips into WRC and NASCAR have both been unsuccessful. He doesn't have too many options left. Of course, I could be wrong, he could be using a year at Williams to show he has still got the talent and desire to succeed, before attempting a move to RBR/McLaren in 2013 once Webber retires.
However, I believe that any move to Formula 1 will be because of money and not love of the sport.