WFS

WFS stands for Web Feature Service. Its an OGC standard for serving vector data over HTTP. See wikipedia:Web Feature Service.

WFS-T is a two side communication extension to this service, making it possible to modify objects on the client side and submit. For example the following Open Source servers are supporting this protocol

• deegree (EU INSPIRE portal will be based on this)
• GeoServer (very popular)
• Mapserver (read only, no WFS-T)
• TinyOWS (new challenger)

There's currently no WFS service containing OSM data available. Demo service at http://188.64.1.61/cgi-bin/tinyows may be available (data only from Finland).