Okay, so ever since I discovered that my Cleveland Public Library card allows me access to e-books and other electronic media, I have been very happy. It's good for finding something to read when the library is closed, or if you are perhaps a little embarassed by your reading tastes, and has lots of newer materials available.
Looking for ways to read using your computer? I've compiled some resources.
Daily Lit serves those pinched for time and looking to catch up on the classics by sending excerpts of classic literature and nonfiction via email or RSS. You pick how often you receive the sections, and read at your own pace. Fairly small selection, but it is searchable.
Full Books has a variety of out of copyright material, ranging from reference to classic to schlock. Online reading only, no searching, and it's all arranged alphabetically by title. But it has P.G. Wodehouse. You'll find some gems within.
World Wide School is set up for those who want to broaden their education and offers a variety of older children's materials, classic texts, and fiction. Again, online reading only, but it has a searchable index.
Munsey's is the place if you've got a love for old genre fiction. Tons of pulp and classic materials. You can download to a mobile reader or Adobe Acrobat or read online in HTML. Searchable by keywords, some books are tagged.
Baen Free Library offers the first books of several science fiction series for reading, along with discussion of whether this is good for writers and publishers or not.
And of course, Project Gutenberg the original e-publisher of free copyright material.