Found another link while I was, go figure, looking for something else. In their own words...

LibraryIreland.com is a free information resource on Irish antiquities, biography, genealogy,
history (general, local and social), literature, and much more besides. You can search the
library, browse the extensive subject index, or subscribe to our mailing list for free bulletins
of what's new on the library. If you find the site useful then there are various ways in which
you can help support us. The latest additions to the Library are featured below. Enjoy!

http://www.libraryireland.com/

And we can't forget, while we're on this subject of free books online...

Digital Library Online - http://digital.library.upenn.edu/books/
Project Gutenberg - http://www.gutenberg.org/
Bartleby - http://www.bartleby.com/