Here's what I do:
six pounds of unpeeled shrimp (split top of shell with kitchen shears)
3 sticks of butter (not margarine)
juice of 3 limes
1/4 cup of dry bbq rub (I use my own brand: Tips, but could substitute another)
In the largest skillet you can find melt the butter and mix in the lime juice and a liberal amount of the dry bbq rub.
place the shrimp in the melt in one layer and cook over medium heat for about 5 minutes. Turn the shrimp and cook the other sides until shrimp are pink (you may have to make in multiple batches). Use the cooking liquid and transfer to individual bowls for sopping with french bread. Be sure to cover your table with newspaper. To take the shrimp out of shells, all you have to do is pinch the legs and they will slide out of the shells from the slit in the top of the shell. Enjoy, Tip