Check out this video and blog post made by Gary Gale of the Y! Geo Blog interviewing various people at Where 2.0. Of course OSM has a presence 🙂
Skip to about half way through to get straight to the OSM bit, but the first 5 minutes are also worth a watch.
Note: Thea, Dirk and Sarah work for CloudMade running events like mapping parties (see here for the blog and events), the video erroneously attributes them to OSM. Of course they contribute a huge amount to OSM, but we have to be clear to avoid flames 🙂