Please let me know what you decide about your smart phone. I am considering one myself... if only to get real time quotes/breaking news on it. I get free delayed (by 15 minutes) quotes on my web enabled Verizon phone now... cost is $5.00/month for the service. If I were to get a PDA phone with VCast service and real time quotes it is $50.00/month as you state. If you think the service will make you at least that much in trades a month it is well worth it IMO... also you will be able to access news as it happens to your investments, a service I cannot get at all presently. That alone makes it worth the $$$$ in my opinion.
Cheers.