Android upgrade, still unlocked?

So i am thinking of buying a samsung infuse for dirt cheap from a friend. But i plan to root it, and install android 4.0.4. My question is; after i do that would the phone still be unlocked and therefore able to be used on any network?

Thank you so much for anyone who helps me.

Rooting shouldn't touch anything to do with the network so you should be fine. Just make sure that the android 4.0.4 update is a custom rom and not an official update because i think it may cause problems.

Thank You