Here’s something all the cool kids will eventually be doing: paperless airline check-ins via smart phones and PDAs. Good for the environment and great for those that easily forget things, paperless check-ins are being introduced by several major airlines including Continental, British Airways, Delta, Northwest, Southwest, Air Canada and Alaska Airlines.

As I understand it, there isn’t a uniform procedure yet. But basically, you check in online via your iPhone, Blackberry, etc. and get a barcode emailed or text messaged to you. You put that barcode under the airport scanner and voila! – you are checked in. American Airlines is calling it “Mobile Boarding” and is now offering it on a limited number of flights. Check it out on their website here.