Hi all,
NutIP is a ROM for HP-41 (C/CV/CX). It implements a full-featured TCP/IP stack and a web server. I never ran the code on real hardware because devices are rare and expensive (one need a HP-41, a HP-IL module, any hardware that let you burn a ROM, a HP-IL/RS232 transceiver...). Though, I managed to run NutIP on emulators. It works well with nonpareil and Emu41.
You can download source code (under a BSD-like license), binaries and documentation at http://perso.orange.fr/kdntl/hp41/.
Hope you enjoy it,
Khanh-Dang