I found this article type deal online. It gives a lot of information about sodium and no/low sodium diets. It lists foods that should be avoided, foods that are generally okay for low sodium diets, and miscellaneous tips and facts. For instance: Did you know, "Food products that are ‘reduced fat’, ‘fat-free’, or labeled as ‘good for your heart’ are often higher in sodium and calories."
There's also a nifty comparison chart between regular foods and their low sodium or unsalted counterparts.
Anyway, I think this little informational packet thing is super awesome. It has a lot of basic and very helpful information to get you started and even lists some websites to get more information from.