You also might want to look at PDABooks.Org which has around 2400 books. Quite a large section of pulp fiction, etc. For the adventurous, you can access the mobile edition of the site at PDABooks.Org Mobile .
From a newbie: I've looked at the Gutenberg site and would like to read several of their selections. Is there a way to convert the .txt files so they can be read by MS Reader? If not what's the best way to read them on my Axim?
if you have MS Word, Microsoft has a 'free' download that will allow you to take any text that can be opened in MS Word, and convert it to .lit for MSReader...
There is also a couple of newsgroups under ebook that have a number of books regularly posted. Some legal, some not. They are in different formats as well.