Here's a site that has a great many e-books some in PDF, some in HTML, and others as TXT which can be modified to be read on palm devices. This includes a slew of G.K. Chesterton, the Catechism and other important works. For those who are not aware, it is possible to get a PDF reader for Palm from adobe. It requires that you convert ordinary PDFs into palm-readable PDFs, but it is very, very nice. (It also allows you to carry around many of the books from the Broderhof collective.)
