I’ve recently seen a fair amount of advertising with phone numbers listed with letters instead of numbers. Listings like 555-SOLD are fine, so long as you also list the digits associated with the letters. My Treo, and many other smart phones like Blackberries and iPhones, doesn’t have a way to associate numbers with the letters advertised. The take-home message is that letters in numbers went out of style with the advent of modern technolgoy and using them as an advertising tool means that many prospective customers won’t be able to call you.