I heard on the news at the weekend that a form will have to be filled out and signed at least 3 months prior to the SSIAs maturing. If not, then (I think) all the profit made on the account will be taxable(including the generous 25% top-up that made the scheme a must-have for every Irish resident!)
Revenue have published instructions on their site so go look at them.
Don’t worry, you won’t have to sign anything until at least 2006, and your bank should send you out the form!