Most of the time, yes. You need to call the cellular provider you want to go with and tell them you want to port a landline number and ask them to check the portability. If it is portable they will explain the process to you.
I ported my landline last MAY and haven't had a problem since.
The only problem I had is that the website said go to the Corp store, and my corp store was clueless and said it couldn't be done. I finally had to CALL at&t and they did it.
