Hi Steve
Me and a friend have written a full-featured TCP/IP-Stack for a C515(c) (HTTP, TCP active/passive, UDP, SMTP, FTP) for use with a 10MBit Ethernet
(see FlexGate). The stack was written with a self written C Compiler (uC/51). The stack is running very stable (up to 16 simultaneous HTTP/1.1 connections without any problems), but the project is still not finished. For use with a modem, we are currently working on a PPP driver (we want to use a 8051 core with a GSM modem as dial-up e-mail messaging system).
Jo