This tutorial is sort of confusing the first time you do it (I had to use my seam ripper at one point), but once you've done it once, it's a piece of cake! I used this tutorial.
1 fat quarter
Regular sewing stuff (sewing machine, scissors, iron)
Step 1: Trim your fat quarter so it's a nice even rectangle with no selvage. Position it so the long edges are horizontal.
Fold the upper right hand corner down until the edges meet up perfectly like so. Iron it so you get a nice crease.
Cut along the crease.
Fold them right sides together so that the "blue" marked edges are together. Sew with a 1/4" seam.
Iron the seam open. Now you can really see your parallelogram in all of it's quadrilateral glory.
Now turn your parallelogram like so. We're going to match up the lines you just made. Match the corresponding arrows
Fold the fabric up and pin in place.
Now sew along the pinned edge.
You should get one looooong strip.
Once you've done that, open it up and fold the two edges in to the center crease you just made
and then fold back in half along your original crease. Iron so it stays in place. You're all done! Enjoy your cute bias tape!