From anecdotal experience we've found that a few people consider connecting an Arduino to the Internet a difficult process. However it is only a little more complicated than blinking a few LEDs - as the example sketches are also included with the Arduino IDE, which can then be modified for your own purposes.
Recently one of our customers articulated how easy it is in their own words, and using ourEtherTen board you can do so as well. So don't take our word for it - visit gene's site for his experience here. And to keep up with other developments - we're on twitter, so follow us for news and product updates as well.
Here at Freetronics we have a range of Ethernet-enabled Arduino-compatible hardware, such as the EtherTen above, and also the mother of all Arduino-compatible boards - theEtherMega:
As well as being totally Arduino Mega2560-compatible, the EtherMega has Ethernet onboard, as well as a microSD socket and supports our optional Power-over-Ethernet regulator. When you need maximum I/O, flash and program memory space along with the other features - this is the board to use.