When you set up ICS Windows will insist that it's IP be 192.168.0.1; which is fine. Your Linux box will have to have an IP on that same subnet (somewhere between 192.168.0.2 and192.168.0.254). You will also have to set the Gateway on the Linux side to 192.168.0.1; this way it will know where to go for addresses outside the 192.168.0 subnet.
Now, from the Windows side you want to allow incoming SSH trafic to be forworded to the Linux box... so from Windows go to the connection properties of your broadband connection (you do have to NICs in this PC right?); go to advanced; go to settings under ICS; click ADD; fill out information... it will look something like this:
Description: Incoming SSH
IP: The address of your Linux PC
Ext. Port: 22?
Int. Port: 22?
I dont know enough about SSH as I would like so those ports maybe wrong. Search the web for the corrects ones or maybe someone else reading this thread can indulge us.
That should work (granted I have not tried it!). You will need a PC extrernal to your LAN to test it... have a friend try to SSh into your Linux box.
Oh.. and make sure you have SSHd running on Linux.