Online Maps with OpenLayers

This colorful map, from the Czech Republic, is using building:levels and other tags to draw OpenStreetMap in 3D http://osm.kyblsoft.cz/3dmapa/?zoom=16&lat=75.7154&lon=14.42162&layers=B

A true 3D map of Moscow has been produced by Russian mapper Dmitry Marakasov http://glosm.amdmi3.ru/about.html

I previously said this map used WebGL, but Dmitry corrects me:

glosm doesn't use WebGL - web map are just prerendered raster tiles,
and perspective screenshots are from native viewer written in C++.
Geometry generated with glosm may potentially be displayed with WebGL
viewer as well, but there's no such thing as of now.

Mappers using ArcGIS: you can download shapefiles and edit OpenStreetMap with this project http://esriosmeditor.codeplex.com/documentation I met one of the developers from ESRI, and he is interested in how it can add to your spatial data of an area or help you contribute to OpenStreetMap. If you or co-workers have ArcGIS, please try out this program and post your comments here or in the Issue Tracker.