QRcodes and Tags
QRcodes and Tags are barcodes suitable for scanning by devices
like the Blackberry, iPhone, or Windows Mobile phone.
With the appropriate scanner application (most are free) you can access information just by pointing your phone at the screen or printed page.
QRcodes look like:

QRcode technology was invented in Japan and is popular in Asia and Europe...and it is catching on in the United States.
Popular QRcode scanners are
Quickmark and
i-nigma.
Microsoft tags look like:

You can learn about them and download a free scanner (many phones are supported) from
Microsoft.