There are several manufactors of Pipes that will fit your machine. Screaming Eagle (HD), Vance & Hines, Sampson, Cobra, and probably at least 1/2 dozen more. You could start by looking at the HD website, then look at JP Cycles (they carry lots of brands) and/or the manufactors site(s).
Usually when you change to a more open flow exhaust, you will also want to upgrade your air intake as well. Also I am assuming that being a 2006, your bike is Electronic Fuel Injection. You will most likely need to have the ECU reprogrammed to insure the Fuel-Air Mixure is not to lean and set correctly for your new Air Cleaner-Pipes set up. Doing so will not only make your bike run better, it will keep you from burning out a piston from running to lean.
You HD Dealer or any Qualified Trained Shop can help you with selection of Air Cleaner - Pipes that will give you the look and performance you are seeking.
Hope this helps....... And Thank you for what you are doing. Come Home Safe.
FM