What cohousing is not: It's not a "commune". In cohousing each person owns their own unit or house similar to a condo association (in fact legally many cohousing groups are condo associations) but unlike a typical condo association there is much more emphasis on sharing resources and building a sense of community between the people. There is a large common house where dinners are served on a regular basis (optional!), celebrations occur etc. Often there is some sort of group daycare. There are usually some shared facilities like an exercise room, arts and crafts area, library, media room, hot tub etc. (depending on the choices of the members). The most important thing is the community is designed by the members who share some values! We hire professionals such as architects and engineers but it is the members who have the final say.
Both Ed and I love our families and are very close to them emotionally but physically they are spread out. Most people today never get to know their neighbors and usually spend little time with them. Cohousing offers a return to the comfort and security of extended family and neighbors you can count on.
This is a really good article for an introduction to cohousing.
If you would like more information check out the Cohousing Network Homepage.