Here's another one dealing with coconut milk and lime juice - I tried this last week, and was VERY pleased with the result. There is another thread relating to it in the Hair Recipe Board.
I'm assuming that you don't want to use heat, otherwise I would suggest a flat iron/pressing comb.
John Frieda's Frizz-Ease RELAX creme works great. There's 2 you can try, 1 is "Moisture Remedy" and 2 is "Straight Forward" which comes in a pump. I use it on my edges and my daughter's natural 3c/4a hair. You should be able to get it any retail drugstore or BSS.