Yes, you can install Steam on any computer, log in with your account and it will recognise that you are on a different system and send an activation code to your email address which will allow you to access your Steam games from that computer. This is a nice feature BUT having a the Steam version has turned into a nightmare for me, my advice to everybody is to avoid the Steam version at all costs....don't be fooled into thinking that the boxed version in shops is not Steam.....it is.
Andy