My class have been studying the history of schools in Ireland recently. If you are near Dublin, it may be worth bringing your class to the Small Lives photographic exhibition at the National Library's Photographic Archive in Temple Bar. It's running until June 2012. If not, you can view photographs from it on their Flickr site.
The NLI have provided some lesson ideas based on photographs of a classroom in Waterford. Click here to download them.
I also stumbled upon the wonderful AskAboutIreland.ie which is very child-friendly. I set the children the task of researching the history of schools in the country using this site. They loved using it. It's bright, packed with information, activities, illustrations and pictures.
Upon further delving into the site, I found some great resources for SESE and Gaeilge. I particularly like the eBooks of Irish myths and legends. There's an audio option for differentiation too. One reservation I have about the site is that the standard of Gaeilge is quite high and that it may be more suited to scoileanna T1 and only senior classes in scoileanna T2.