Have you heard of QR codes yet? Here is a quick introduction:
“They come to us from Japan where they are very common. QR is short for Quick Response (they can be read quickly by a cell phone). They are used to take a piece of information from a transitory media and put it in to your cell phone. You may soon see QR Codes in a magazine advert, on a billboard, a web page or even on someone’s t-shirt. Once it is in your cell phone, it may give you details about that business (allowing users to search for nearby locations), or details about the person wearing the t-shirt, show you a URL which you can click to see a trailer for a movie, or it may give you a coupon which you can use in a local outlet.
The reason why they are more useful than a standard barcode is that they can store (and digitally present) much more data, including url links, geo coordinates, and text. The other key feature of QR Codes is that instead of requiring a chunky hand-held scanner to scan them, many modern cell phones can scan them. 
Your business, no matter how small or large, could use QR codes in a number of ways. You could add one to your business card or t-shirt containing your contact details so its easy for someone to add you to their contacts on their cell phone.
Also, you can add them to any print advertising, flyers, posters, invites, TV ads etc containing:
Product details
Contact details
Offer details
Event details
A coupon
Twitter, Facebook, MySpace IDs
A link to your YouTube video
While many people are not familiar with QR codes yet, the are quickly catching on. Have your t-shirts printed with QR codes today and people will be scanning them in no time!