Eye-Fi Wireless SD Card
If you're using a dSLR or other digicam that doesn't have built-in Wi-Fi, there's still hope. The Eye-Fi Wireless 2GB SD Card ($100) packs 2GB of storage (obviously) and Wi-Fi functionality into a normally-sized SD card that's compatible with any SD-capable camera. Send pictures wirelessly back to your computer, printer, or to your favorite photo-sharing service, including Flickr. A great way to add some functionality to an older camera.
[Thanks, Todd]