Feeling a bit left out while other big manufacturers call loads and loads of their cars back home (or at least into dealerships), BMW decided to do the same and issued a 3-series/dealer reunion, concerning all Neue Klasse successors built between May 99 and August 2006, or all E46s except for the very early ones.
Why the recall? Well, in rare cases a gas generator (whatever that is) connected to the co-driver's airbag, delivered by an external supplier, could burst out spontaneously. The difference to the GM recall affair is that so far no case where this happened is known of, and the action taken is a voluntarily precaution by BMW. Good for them.
So if you own a 3-series of that period, get ready to drop by your dealer to get the passenger airbag replaced. It will cost you nothing and be done in about an hour.