Nothing like 4 month old reply
In case anyone still wonders, yes this has been done many times by people who used computers based on the 6502. I mean the commodore 64, apple II, atari 800, etc. Today there are cross development tools for unix, mac, and pc (dos/windows) with assemblers and simulators, and several very good multitasking kernels, full ansi C compilers, unix like mini systems and so on.
The best place to look is on the enthusiast sites of these home computers. Look for "commodore ring" for example and that will lead you there. Also search for "commodore assembly".
For a tcp/ip integrated into a full web browser, see Maurice Randall's The Wave.
http://www.ia4u.net/~maurice/gbrowse/wavesource.htmlAlso search for "Poldi's Slip".
These software are meant to work with a UART, in some cases there are drivers for direct i/o with a CIA port (3 wire software interface).