pants to shorts

I'd love for you to show us how to make shorts out of pants. I have a hard time getting the legs even, I can get the inseams right but I'm not sure how to get the outside seam right. I either end up with shorts that aren't straight across the bottom (short on the inseams and long outside) or one leg is longer than the other. Do we measure down from the top or up from the hem?

This would be great for women's sewing month!

Legs are tricky.  I've found that it usually turns out straight when I measure both from the top down and bottom up.  If they are different from each other then I usually follow the bottom up measurements.  Also, make sure when you're measuring and cutting that the pants are folded right.  Don't cut with the pants opened up.  Fold the pants in half with the inseam NOT on a fold, but in the middle (like when ironing a pair of slacks). 
There's more info on altering pants in our blog.  Check out this article for more altering ideas: http://sewmamasew.com/blog2/?p=487
Hope this helps!