new to cingular from verizon

[fondoo]

I'm interested in porting my verizon number to cingular. i like the fact that I can use an unlocked phone when i travel back to asia every winter. I'm also interested in purchase a Treo 680. I already have a Treo 700p Verizon Wireless. Cingular lowest plan is 450min for $39.99. Is there any lower plan that 450min's? All I need is 300 min's per month and no data plan needed.