So what does it actually mean? Adding Virtual Earth tiles to ArcGIS Desktop/Explorer? First off, this isn’t a free service. The ArcGIS Online Premium Service: Virtual Earth Maps Collection will cost you. How much? Not a clue. I’m sure it will be at a price point that will make some jaws drop and others will remark how cheap it really is. See the bottom of the post for pricing. One thing to keep in mind as well, “You must use ArcGIS 9.3 to be able to connect to ArcGIS Online Premium Services”. This means that if you are on 9.2, you’ll need to upgrade to enjoy the Virtual Earth maps and aerial images.
What about ArcGIS Explorer? It too can take advantage of the Virtual Earth service. But it will also require a subscription to the premium maps. If you want free access to Microsoft’s imagery in a 3D globe, you’ll have to use the 3D control in the browser (or NASA World Wind assuming that thing still works).
Now what about Server? This agreement only covers Desktop and Explorer. Thus you’ll only need to continue using it the way you already are. No big changes here. What about existing Microsoft licenses? That would appear to not cover this agreement, you’ll have to re-license data from ESRI for ArcGIS Desktop and Explorer.
ESRI operators are standing by to take that order for Virtual Earth data
Update: Jithen?says that the cost will be $200/user a year.