Maps and placenames
Google maps - satellite images and maps
GeoHive - an initiative by Ordnance Survey Ireland to provide easy access to publically available spatial data.
Mapquest - Excellent range of maps and atlases for worldwide cities and regions, with points of interest and other visitor information.
Perry-Castaneda Library Map Collection - is an extensive map collection owned by the Perry-Castaneda at The University of Texas at Austin. Many of the maps in the collection have been scanned and are available online, and most of these maps are public domain.
OSI Historical mapping - a comprehensive archive of Ireland's ordance survey maps both historical and current.
Placenames Database of Ireland - is a database and archive of place names in Ireland.
Northern Ireland Placename Project - information on the origins and meanings of over 30,000 place-names from all over Northern Ireland.