Are you sure you mean the aptitude tests and not the interviews?
The aptitude tests finished some time back and now the interviews are in session as far as i know.
Anyway there's some more info on them either here on Pprune (look for "A day in the life of Aer Lingus") or you can go to http://fly.to/wannabes and check out the Aer lingus section.
Hope it helps.
