The first thing you will need is a mobile PC device. There are plenty of inexpensive devices that can be used as an ebook reader. Devices include tablet PC's, Ultra Mobile PC's, Netbooks, and even Laptops. Many of these devices can be found for $200-$300 which is comparable to a Kindle or Nook. Also you can use these devices for much more than reading such as email, web browsing, or documents.
The mobile device is going to need to have the operating system modified. The device will either need a new mobile operating system installed or modify the existing one on the PC. If the device has touchscreen you will want to create buttons and icons that will easily be accessible. Also the coloring, background, and shading may need to be altered to suit reading.
Next is the ebook reader software needs to be installed. There is plenty available for free to download from the internet. There is Adobe Reader, Calibre, FBReader, uBook, Microsoft Reader to name a few. There is a lot of options for eBook readers. There are readers for books, comics, magazines, and newspapers.
Store up ebooks for your new ebook reader. Project Gutenberg is a favorite place to get free ebooks. Use the free ebooks link from FBReader.org for a list of ebooks to download.