Answered well above... but check your state laws... some require you notify, some don't...
Too be honest... now, as a 25 year vet of the police line of profession and knowing what I know, and seeing this new "breed" of police officer in action... if you don't have to by state law, then don't... (unless they may see it somewhere... ie: if it's in your glove box, and you need to go there for your car registration then tell them before hand... "Officer, just to let you know I have a CWP and a handgun in my glove box, that is also where my registration is, May I open it to retrieve the documents?" and wait for a answer... but it is best to keep it truly concealed and in a different area of your paperwork... IE: center console...
The reason I say this... is in the past I always believed that for the most part we cops were always right besides a few bad apples, and that citizens and the press who made up crap against us were just bitter... and in most cases that is true... but I've seen my fair share of questionable stops, questionable searches, and unnecessary detainments by officers, mostly new ones... now I may have not been a angel my full 25 years as a cop... but I always thought of us as the good guys... now, when I back up these younger, more about the ME officers...when someone says they have a CWP... they ask where the weapon is, get them out of the car, find the weapon, and run it... BS IMO, (unless you have a honest opinion that somethings not right here...) if someone tells you they have a CWP and shows you the permit, they shouldn't be harassed for their honesty. IMO
Not sure whats going on, but in the last 2 to 3 years I've had a fallen out with my profession... mostly because of the type of recruits we are getting... college kids that want to prove how bad ass they are to everyone... I've kicked my share of ass, but feel that I lived by a good and honest rule... respect me and I'll respect you... disrespect me and game on.

(and most citizens show respect... I can tell when I'm being deceived or played within minutes of a contact.)
5 years till retirement and counting.