For those that dont know .. metro pcs has plans starting at $40 + taxes for unlimted national calling (cheaper for unlimted local calling only)... and $45 for unlimited us + 100 counties... its pretty sweet big draw back is that its not availble everywhere so if you travel alot you will find dead zones and probably have to pay roaming.
www.Net10.com ... thier pretty good as well .. My daughters phone is from them. Its a prepaid service but i have hers auto buy $15 a month - 150 mins. I beleive it piggy backs ontop of the sprint network. Its a flat rate of 10c min US calling and 5c text msg to anywhere in the world. So works out as a $16 a month cellphone bit hard to beat.