johnfás and Zhou said it all really, there's not much more you can find online for free. Up-to-date textbooks really are the best way to find out if and how a given law has been treated by the courts, unfortunately you're unlikely to find many of them for free of course.
If it's legal discussion and analysis you're after the blawgosphere is rich and diverse, and can also help in keeping one up-to-date on the law. There are many out there, but depending on your area of interest there may be one or two I could recommend (unfortunately I don't know of any Irish constitutional law blogs).