The Canon Wireless File Transmitter E3(A), or WFT-E3(A) for short, equips the EOS 40D digital SLR with Wifi capabilities, allowing you to transfer images wirelessly to a computer or even direct to a website or ftp server. The Wifi also lets you wirelessly remote control the camera, including a live preview of the scene on your computer monitor. You can even remote-trigger the camera from a website.
If you’re after higher performance, the WFT-E3(A) also includes a wired Ethernet port, giving you close to the speed of the camera’s supplied USB cable, but over much longer distances. There’s additionally a full-size USB port which lets you connect external storage devices for backing-up images, or recording files as you take them. This port can alternatively be used to connect a compatible GPS unit to store your exact co-ordinates in the image header. Read the whole article here