The best free ebook reader for the Windows Mobile is hands down the Mobipocket reader. This free application is for Windows Mobile, Desktop Computers and various other handhelds. It features autoscrolling, like movie credits. It also allows you to make ebooks out of Word, HTML, PDF and many other document types. It has a direct connection to an ebook store. If you install a dictionary it will look up words from out of the books. If you install a book on your desktop, when you dock your handheld it automatically syncronizes your books to the handheld. Not only that but it allows you to annotate your books with bookmarks, highlighting, notes etc. The annotations also synchronize with your handheld. There are lots of books to choose from on the site, dictionaries, medical books, bibles etc. Plus you can build and sell your own with encryption using the free Creator app.
Direct link to Windows Mobile cab
Palm Treo 600
Audiovox PPC 6600
Mogul PPC 6800