Why is it worrying? They stopped because EU enviornmental requirements call for no lead in products, so they're probably going to just come out with a new version of each product that has no lead in it (the current ones' circuit boards are assembled with lead-based solder).
And keep in mind that Apple is not (by ANY means) the only manufacturer of WiFi equipment. Not by a LONG SHOT! Any (and I mean ANY) 802.11 compatible product will work with the AirPort card in your computer.
Take a deep breath and relax-it's not a real problem, just a glitch in availability.