I am very new to using Agile (scrum). we have planned sprints using story points, but have not assigned work (tasks) to all the user stories in the project, just in the sprint coming up. My boss wants to know how much work is left to do...and I don't know because I haven't planned those sprints. Can anyone give me advice or a resource to reference on what I need to do in order to provide him with what he needs?
You can't because if you have a new project and/or new team, you have no known velocity. After a few sprints you will be able to say something like "The team can do 35 points per sprint". Then you will be able to approximate how many sprints it will take to accomplish the entire backlog or how long it will take to get to a particular story.
You do have your first impediment already though. Your boss obviously does not understand scrum or hasn't bought into the agile philosophy if he is asking that question before you even start.
Even after you get going you don't give estimates in hours for future iterations. You use story points (based on you past experience) because hour units are way to precise for anything other than the current sprint.
If you are using TFS there are a number of (Reporting Services) reports that come out of the box, not sure if they include exactly what you want, but there is also the option of creating your own.
Not sure how good these links are, but they should give you some more to google on.