Before I forget and Ulysses dissapears into the distant past these are some really good links that have a combination of serious facts, free copies of the book and an animated version of the story that is worth looking at whether you intend to read Joyce's work or not.
A good start would be the Ulysses site edited by John Barger with links, analysis and timelines for the characters
The Brazen Head is a site with a similar ambition to be the start for all things Joyce and this looks at the author on a much wider basis than just Ulysses
Wikipedia is always worth a check for the essentials and it points to some of the links summarised here
Project Gutenberg of course has the text if you want to try it without having to go out and find a copy of the book as does the One page of Ulysses a day blog
For a great audio guide through the book, with lots of insight into the characters and the locations you cannot beat the RTE Radio 1 Irish radio Reading Ulysses series
For light relief try the Ulysses for Dummies site with its animated version of the epic
Hope they help if you set off to read Ulysses the RTE site really helped me to get to grips with it all and some of the other sites have got me ready for more Joyce