Not for tourist guides - available at many independent bookstores or amazon.com.
I love these guides. We have one for Boston which we'll use today and the one for DC is equally as useful.
I'm a big fan of alternative guidebooks, not the Fodors, Rick Steves or Frommers variety, but more like Time Out or Cadogan. In France I like the Routard guides and the Paris est a nous, which I have blogged about in the past.
The NFT guides are great local guides with hints on parking, where the nearest good food is and the maps are easy to read. I recommend you pick one up the next time you are going to Boston, Philadelphia, San Francisco or Chicago or another fine metropolis.
Other good on line guides include Gridskipper and I'm always happy to search and post on Egullet and if it is seat pitch, airline lounges or what they are serving in first class Paris-Singapore I'll happily use the search function on Flyertalk.
Me, I'm looking forward to dinner at Durgin Park (I know, I know, but the coffee jello...) and lunch and Lock Ober.