Creating old looking paper is pretty easy to do. I used this method to create pages for my diary project on "The Crucible" in my Advanced English 3 class.
Step 1: Turn On The Stove
Turn on your stove to a setting between low and medium. I usually set it to around 4. Let it sit for a while.
Step 2: Lay Your Paper On The Stove
Hold the paper by one end and lay the other end on the stove. Slowly move the paper around so that each spot gets heated thoroughly.