You really can't do much with a Terms of Service contract like this!
"Prohibited and Permissible Uses: Data Service sessions may be conducted only for the following purposes: (i) Internet browsing; (ii) email; and (iii) corporate intranet access (including access to corporate email, customer relationship management, sales force automation, and field service automation applications). Prohibited uses include, but are not limited to, using Services: (i) with server devices or with host computer applications, including, without limitation, Web camera posts or broadcasts, continuous jpeg file transfers, automatic data feeds, telemetry applications, automated functions or any other ?machine-to-machine applications; (ii) as substitute or backup for private lines or dedicated data connections; (iii) for Voice over IP; (iv) in conjunction with WWAN or other applications or devices which aggregate usage from multiple sources prior to transmission; (V) Using the Services for any activity that adversely affects the ability of other people or systems to use either the Services or other parties' Internet-based resources including, but not limited to excessive consumption of network or system resources (whether intentional or unintentional) and "denial of service" (DoS) attacks against another network host or individual user; or (vi) Interference with or disruption of other network users, network services or network equipment. except for CONTENT formatted in accordance with cingular’s CONTENT standards, Unlimited plans cannot be used for uploading, downloading or streaming of video content (e.g. movies, TV), music or games. Furthermore, unlimited plans (except for DataConnect and Blackberry Tethered) cannot be used for any applications that tether the device (through use of, including without limitation, connection kits, other phone/PDA-to-computer accessories, Bluetooth® or any other wireless technology) to laptops, PCs, or other equipment for any purpose. Service is not intended to provide full-time connections, and the Service may be discontinued after a significant period of inactivity or after sessions of excessive usage. Cingular reserves the right to (i) limit throughput or amount of data transferred, deny Service and/or terminate Service, without notice, to anyone it believes is using the Service in any manner prohibited above or whose usage adversely impacts its network or service levels and (ii) protect its network from harm, which may impact legitimate data flows. You may not send solicitations to Cingular subscribers without their consent. You may not use the Services other than as intended by Cingular and applicable law. Plans are for individual, non-commercial use only and are not for resale. Security: CINGULAR DOES NOT GUARANTEE SECURITY. Data encryption is available with some, but not all, Services sold by Cingular. If you use your device to access company email or information, it is your responsibility to ensure your use complies with your company’s internal IT and security procedures. "