ArcBruTile

ArcBruTile display basemaps from OpenStreetMap, Bing, MapQuest, CloudMade, Mapbox, Stamen Design and others in ArcGIS Desktop.

ArcBruTile also solves the projections problem: all tiles are transformed on the fly to the desired projection if needed. ArcBruTile makes it very easy to combine data with different projections.