The pimp shirt can be as simple or as complex as you want it to be. One option is to just go with a normal dress shirt and make it shine with accessories. This route is simple and needs no further explanation.
Another option is to wear something outlandish to accent your suit even more. This can be something with a wild pattern on it or a unique cut. Look for something with wide collars and long cuffs.
Quick Tips
1. Wear something that fits.
2. Don't buy anything outlandish if you plan on wearing a tie.
3. Do wear something unique if you plan on going without a tie.