If you are into yuri manga, Lililicious.net is a quality site. English versions of stories like Maka-Maka, Indigo Blue, and Yuri Shimai are ready for download. The books are in JPG format. Most computers automatically have a program installed that will read JPG files.
Download the issue you want to your computer, it is one big zip file. Then double-click the zip file to see the JPG files for each page of the issue. For convenient viewing, use Windows Picture and Fax Viewer (See this article for Viewing PNG Files to set it up. Anywhere you see PNG, substitute JPG instead.)
As yuri is a genre that is harder to find, this is a great site.