im am also having the same problem , and a few others as well with samba, but anyway.
i enabled internetconnection sharing through the wizard in the contorl panel/MMC.
i disabled the firewall because i knew it would cause me problems, and the win xp computer (192.168.0.2) can not browes the web at all.
and yes i also read the how-to's yet still no ICS, my linux box is mandrake 10.
yesh the computers can ping each other and ive got samba half working, the windows box can see the files ive shared on linux,
linux can see the windows box, and the workgroup name, how ever it thinks that nothing is shared(but there is).
im not to woried about the SAMBA problems right now, if any one can shed some light on the internet connection shareing theat would be good,
thanks heaps :D