AT&T has introduced a new tariff for customers with disabilities, offering unlimited internet and messaging usage for a set fee.

The Text Accessibility Plan (TAP) for iPhone is designed to give iPhone customers with disabilities the choice of unlimited text messaging, web browsing and easy access to email for $40 a month.

"Our Text Accessibility Plan allows customers who are deaf or have hearing or speech disabilities to literally tap out their communications on the go," said Carlton Hill, vice president of product management. "Now with TAP for iPhone, users can tap, flick and pinch the innovative Multi-Touch touch screen for a completely new world of functionality."

This new plan is available to new and current iPhone users with qualifying disabilities through AT&T's National Center for Customers with Disabilities (NCCD). To qualify, customers must complete an application for eligibility.

During the iPhone activation process, customers sign up for a standard iPhone voice and data plan. After the iPhone is activated, customers can e-mail, fax or mail the eligibility form back to the NCCD to change their rate plan to the TAP for iPhone.

Current iPhone customers who qualify may also submit the NCCD application to request the TAP for iPhone.

AT&T offers TAP plans to qualifying customers for use with most handsets across AT&T's portfolio.