I personally believe that it is proper to carry arms openly whenever possible; the benefits of this are something we spoke of years ago, and I haven't changed my mind.
Nevertheless, for many people concealed carry is the only possible carry. The usual solution is to carry some sort of holster, but another option is to wear clothing designed for the purpose of carrying concealed weapons. The specialty industry built around this second option includes fine craftsmen like those at Coronado Leather, as well as larger-scale manufacturers like 5.11 Tactical.
Apparently, though, Woolrich has begun a line aimed at those who wish to carry a firearm in a fashionable way. Under Armor, which pitched a military-approved version of their undershirts to help soldiers and Marines stay cool in Iraq, is apparently also in this market.
Woolrich is the most interesting, though, because it's such an ordinary part of American culture. It was there nearly two hundred years ago when we were pushing West and needed warm things against frontier weather; these days, Woolrich products are available for sale in every Cracker Barrel by every interstate in the country.