What about the combination ATMega163 and RTL8019AS ethernetchip? First, you could go to www.edtp.com and download (at the webcam link) the hardware en software for the Packet Whacker (imageCraft C). A 30 days evaluationversion is available at www.imagecraft.com. If you want to experiment more, you could have a look at http://members.home.nl/bzijlstra and check how I translated the ImageCraft C source to a BASCOM-AVR source. Tricky, this is a 8051-site and I am talking about the Atmel163, more tricky perhaps, I am not talking about assembler or C but about Bascom-AVR. More info on www.mcselec.com