Science Foundation Ireland's Open Access mandate became effective from February 1st 2009.
The policy is clearly outlined on the SFI website under 'Grant policies'. The full text of the policy is available here.
It covers peer-reviewed papers, conference papers, reports, monographs and datasets and generally follows the EURAB recomendations.
Now all Irish funding councils but one have open access policies: the Higher Education Authority (HEA), the Irish Research Council for Science, Engineering and Technology (IRCSET), Science Foundation Ireland (SFI) and the Health Research Board (HRB)). The HRB has OA recommendations which are expected to become mandatory later this year. All of the others have Open Access mandates in line with the EURAB recommendations. Apparently discussions are underway in IRCHSS which is now the only Irish funding council without an open access policy.