Steve,
I guess you're looking for a software stack.

Have a look at:
http://www.forthinc.demon.co.uk/chipdev/m...cronet.htm
http://www.iniche.com/products/tcpip.htm


Some harware related links:
http://www.leunig.de/en/produk...ndex.shtml
http://www.ibutton.com/TINI/index.html
http://www.picoweb.net/
http://www-ccs.cs.umass.edu/~shri/iPic.html
http://www.embeddedethernet.com/
http://www.mycal.net/wsweb/s7600/
http://www.lantronix.com/
http://www.beck-ipc.com/products/...products_a
http://www.scenix.com/embinternet.html