Hey, curly and wavy heads! I don't know if you've heard about this product (it's not really new). I picked up as little sample bottle at my local Walgreens and gave it a try. I sprayed a few spritzes (several, actually) on freshly washed damp hair before I blow dried.
OMG--not kidding, my hair looked like I used a flat iron for the next two days. This stuff seemed to really work. But I always try things two or three times before I truly BELIVE.
The next time I used it I sprayed quite a bit less and the results were less. My normally curly hair was less so, but still not nearly as straight as I got it before (from just this product and a blow dryer).
After a few more tries (and an investment in the full-sized bottle), I've found a recipe that works for me pretty well. I lift my hair and spritz around my head plus one full spritz on my bangs and another generally over the top of my head--about 5 or 6 in all. Then I add a little of my beloved Kerastase oil and blow dry for a nice, smooth finish.
This one gets a full thumbs up from me!
*Caveat: My hair is fine and curly and fairly easy to straighten with a blow dryer. If you have super curly thick hair (like my daughter) it won't work nearly as well. I've used it one her and it helps slightly, but not much. Great for you who have fine to medium curly or wavy hair :)