Just finished find the Elder Scroll and talked to Pathurnax and battled Alduin. Next step is talk to the Jarl of Whiterun, when I enter Dragonsreach I'm instantly attacked by guards, wizards et al. I'm sure I've not done anything to warrant this, do i have to go back and do the quest again? (Noooooo!!!!) or is there anyway I can make them like me?

Sheath your weapon and maybe they'll stop.