Here is the site I used to decide on a cell phone and rate plan:
http://www.cheapcellphones.com/
Link directly to rate comparison:
http://www.cheapcellphones.com/cellularservice.htm
Based on my needs, I chose the AT&T digital nationwide one-rate plan and an Ericsson R280LX internet phone.
Link to AT&T one rate plan:
http://www.attws.com/personal/buy/select_rate_plan.jsp
I bought the phone at Best Buy where I got $100 in rebates on a $99.99 phone.
I called AT&T directly to start my service.
For $60/month you get 500 minutes of airtime good anywhere in the country, no long distance(U.S.) and no roaming charges. You also get free voicemail, nationwide text pager service, caller ID, and digital. In addition, the small internet screen allows free internet access to some sites and the time spent on the internet do not count towards your minutes.
Hope this is of some use.