Actually, Sprint and Alltel do roam with each other...Here is the article.
http://www2.sprint.com/mr/news_dtl.do?id=11820


<KyleDP123@lycos.com> wrote in message
news:1172163119.471756.253040@m58g2000cwm.googlegr oups.com...
>I live in Ann Arbor, MI, in a building where Verizon literally doesn't
> work one step into the doorway. Sprint has better coverage right here,
> but I guess if I could roam on Sprint, my phone would work too? So I'm
> guessing Verizon doesn't roam on Sprint? That's unfortunate because
> I'm pretty sure Sprint roams on Verizon. I'm on a current AC plan. Any
> explanation or suggestions?
>
>