the will usually only index the top page of a site unless you tell them not to. Which is a good thing. Basically they'll index the first page of a site that you submit, if you want them to index each page, submit each page, and watch your ranking plummit. They'll follow the links on your site, if they lead to other areas of your site they ignore them, if they lead to other sites they'll index those sites and so on and so forth.

Chris