Recently while running through La Petite magazine I found this great tutorial for painting your kids (ah hum.. yours too!) jeans! I have yet to put paint to fabric, but just in case you need to spruce up your look here is the tutorial! EASY peasy!
I know this is hard to read - but all you really need is the stencil some sponges and fabric paint! Put a piece of cardboard inside the pants so that the paint does not run through the leg. They suggest you start at the bottom of one leg and then work your way up.
For full instruction go to La Petite magazine and see the full story (with larger text!). Please send me photos if you manage to get anything onto your jeans and I will do the same... I am planning a bit of a wave print... we shall see...!! La Petite