we recently started a belgian workgroup focused on developing OSS plugins for the Eclipse platform. It seems that several people have been busy last year writing OSS plugins for Eclipse, but they all suffer from the same OSS diseases: lack of momentum, lack of community building, lack of "critical mass". We had a few meetings, mainly knowledge transfer on Eclipse and its APIs. we are also setting up a XP tryout track. We have some expertise in the group on portions of XP (testing, building). OTOH there are still some blind spots (stories, planning game). Also, XP is sometimes stated in non-OSS terms (where is the "customer" in an OSS project, what does "on schedule" or "performance" mean in a OSS context ?).
We are in contact with the belgian XP user group. To get us started, we organize a "XP game" session where we will test XP on a fictive plugin project on design patterns.

If you are interested and live in Belgium (meetings are held bi-weekly in Ghent) please visit our brand new mailing list at sf.net/projects/bigsplash -> lists or contact ac0dr at users.sourceforge.net

see you there!