Adding Openstreetmap to ArcGis 9.3.1

See the Wiki for a list of WMS services using OSM.

Somebody asked a very similar question over on gis.stackexchange.com. Amazingly(*) it seems there isn't a very simple way to bring in a standard tile layer in ArcGIS 9.3.1.

There is a plugin called ArcBruTile which lets you bring layers from various pre-defined tile servers including OpenStreetMap. (TODO: Add more how-to info and a screenshot on our ArcBruTile wiki page)

Alternatively you can bring in WMS layers. This is the old GIS way of doing raster layers, which ArcGis handles easily. OpenStreetMap is served as a WMS by a number of providers as Frederik said.

(* It's a feature which seems obvious to me as a way of making map browsing life easy, e.g. to layer other data on top of, but they've only got around to adding that in ArcGIS 10. I'd love to say QGIS developers have done better, but well unless there's now an easier answer to this question... not really )