Cell phone for snow bird

Getting to be that time of year when an old man's thoughts turn to
warmer pastures in the south. In previous years we've taken our Telus
Mobility (B.C.) phone with us and have paid dearly in some cases for
roaming charges, in some cases as high as $6.00 per day. Now I'm
thinking of getting one of the U.S. cell phone providers for the time
we're south of the border, preferably one that would allow roaming in
the western U.S. (CA, NV, AZ, NM, etc.) without exorbitant additional
charges. A U.S. mailing address would be no problem.

What I'm after is a plan that would not require a long-term contract,
nor do I require a "free" phone. I'm not all that concerned with the
amount of minutes/month as much as being able to be reached. A
reasonable long-distance rate plan would also be a plus, but I'd be
willing to use phone cards if necessary.

I'd appreciate any ideas or suggestions.

Paul