Wel....it goes like this:

I have two computers at home, one sharing the conection to internet (Windows XP with Firewall activated) and another one with Slackware10 Linux with the SSH server.
I would like to connect from university or other places trough SSH to my Linux machine, but obviously the petition goes through the Windows machine first.

After having read some articles and stuff about NAT firewalls and port-forwarding I activated the port 22 in the Windows Firewall to be redirected to my Linux machine but when I make any kind of petition I just get "connection refused" error.
After reading more stuff I think the problem may be with my Linux machine because I have done everything possible with that firewall to activate 22 port.

Any suggestions on how to get it?

May be you should post your firewall rules on your Linux box.. Can you connect to your Linux box via SSH from your windows box? If no, then there is a blocking rule in your Linux box' firewall configuration; if yes then the problem is in your windows firewall's port forwarding configuration.

Using 192.168.0.2:22 I can connect but if I try to use 200.116.xxx.xxx I get the refused connection, so the problem might be in Windows? Anything to do?

Then i think problem is in windows box. You can use `tcpdump' in your Linux box and analize the packets (port number, destination and source IP, for example) related with SSH to see if there is any traffic coming from your windows box.

After a grep of a big dump I found nothing about ssh, I better try to wrestle with windows and get something out of it, thanks anyway!