I'll leave it to others with better links to answer that, but first you need to read Dr. Atkins' book. That's the key.
But, in my experience, you certainly do NOT have to buy a lot of prepackaged (especially Atkins-branded) foods to do this diet. In fact, I only buy Atkins ice cream (because there are no competing brands in my area yet), low-carb bread from an independent baker and Carb Solution snack bars.
The packaged stuff is really way, way too expensive, especially the Atkins brand - competition hasn't really appeared yet and the demand is huge.
The good news is that your supermarket supplies everything you need for the diet in the dairy, meat, frozen and vegetable/fruit departments. You don't need the packaged stuff at all.
And you can make your own substitutes for goodies for much less. For instance, I bought a Liss cream whipper, some NO2 cartridges and I make my own zero-carb, no-sugar, flavored whipped cream with Splenda and sugar-free Italian syrups. Great on jello, Atkins ice cream and especially fresh strawberries. And my friends had never tasted blueberry-flavored whipped cream before - thought it was great!
Read the book, give it a try - you'll find it's a pretty easy dietary change . . . . not a "diet".
There's all kinds of sites on the net.
The best one is atkinsfriends.com
There's all kinds of choices available out there. The market is responding and there are some really good substitutes. I just found a really good chocolate milk substitute that is really good from lecarb.net. I never really drank chocolate milk much before, but every once in a while I like it and this was a really good substitute.
Then you're in the right place... Get on Carlo's ping list!
There are some really great recipies that he's posted, as well as many others...
I have one for Galic encrusted chicken breast with (or without) Alfredo Sauce, where the majority of the carbs actually comes from the garlic! And the alfredo sauce is very low carb, and great on brocolli or cauliflower too.
Mark
My son is a reciently diagnosed diabetic and I've found that now is a great time to avoid carbs for everyone. There are candies, ice cream (4g of carbs per 1/2 cup), diet drinks, etc, etc, etc.. Just go shopping and look. You'd be surprised at how much variety is available.