Dag Nabbit! Design Sponge beat me to the punch. I had a project like this all lined up, but put it on that old back burner.
Your gain. DIY'er Brett Bara has already put together a dandy little tutorial on DS showing you all you need to know to dress up a difficult window with your favorite fabric.
See the list of materials and supplies you need to make a fabric covered roller blind here.
Be sure to sew this. If you use adhesives, they they tend to give out after a while.