changing ssh listener port?

[A. Jorge Garcia]

Whenever I install a dual boot machine, I issue the shell command

update-rc.d ssh defaults

Now I did this on my home PC so I can ssh to it from work (b/c they block every site under the sun...). This worked well for my getting to my email, etc. But suddenly it doesn't work. I'm thinking that the IT guy got wise and blocked port 22 so I cen't ssh home. How do I use a different port?

TIA,
AJG