I've seen this problem mentioned in newsgroup posts, thought I'd just add what I could to the database. I'm in Canada, about 90K km on the car. Had it in to the dealer today, they check the cars regularly for this problem, and told me the car's head gaskets were starting to weep. Still under warranty, so no issue to discuss with them. The gaskets will be replaced, free to me, as soon as we can set up an appointment.
I don't know about other country warranties, but in Canada, owners should make sure they check carefully for this problem before their cars reach 100K!
Larry Van Wormer