Jennie at Missouri Star Quilt Company has a super video tutorial on making a portable ironing pad like the one she uses. I just watched it yesterday and intend to make myself one.
Go to
http://tutorials.missouriquiltco.com/ and select "See All Tutorials". It's the 2nd from the left, ninth row down.
Or go to YouTube:
http://www.youtube.com/watch?v=2uGVYK-VeNs