We call them "light-up" tutu's, but the name is a little deceiving - they are really just tutu's with lights. You just make a regular "knot" tutu, but make sure to make it at least double thick (I like four layers of tulle - two on each piece of the knot cross, if that makes sense). I get the light strand necklaces at Pricebusters or some of our local craft stores - they are tiny strands of led lights in holiday designs (tiny pumpkins, shamrocks, etc) so they still look pretty (and not like lights) when they are turned off. Then I stitch the necklaces onto the tutu, a couple inches down from the waistband - if you are going to wrap the waist with ribbon, make sure you do that first or it will get all tangled up. Actually, I always do the sewing on last after all the other decorating is done. I baste every few inches and voila! Light up tutus that you can turn on and off.
Just make sure to NEVER leave a child unattended in one of the light up tutu's! The battery compartment is pretty well sealed, but it contains those little button batteries that could really burn a child's throat if they swallowed it.
Here is one I made for a Halloween birthday. I don't have any pics of it lit up, though - as soon as I finish it, I will post my daughter in her shamrock one all lit up!
The little pumpkins are the lights! They glowed a really cool orange and just gave the whole tutu a cool look!
And thanks for the comments on my cutie Jack! He was so serious fighting vader! He is going to have a cow when Darth Vader brings in his birthday cake (my hubby is a total star wars nerd and has wanted a vader costume for years - he already has an authentic storm trooper one - so I finally broke over and told him he could get it if he would be willing to serve as birthday party entertainment). We aren't telling him, so it will be a total surprise for the little guy! My hubby has had to miss so many of Jack's birthdays, we are really making 5 a special party!