Here's another story with some more details.
http://www.dailymail.co.uk/pages/liv...e_id=1811&ct=5
It looks like someone took shots at another candidate today. And that Bhuto was shot as well.
Grizzly details aside, I have a hard time seeing how much good will come for any side in this. Whether or not Musharrif (or any of his people) was behind this, there will always be a cloud of suspicion over him (see: Kennedy, Pope John Paul II). If the Islamists did it, I don't see what they can possibly hope to gain from it.