Ron,
I'm not sure about your specific phone, but here's what I can tell you.
Wireless Carriers, like Sprint, do offer "data" plans. Check with Sprint to see specific costs. Sprint would be your internet provider, you don't need to sign up with a third party.
Finally, there are data cables for USB to computer. I personally use Verizon Wireless, and I have a data cable for my Motorola for connecting to the internet while on the road.
My best suggestion is to check Sprint's web site, or contact a local Sprint store. They can direct you to what phone models do & do not have data cables. I just looked up your phone, and it is 1X data capable. Or, have you considered a PCMCIA card for your computer. The carriers offer those as well.
Rich