This is yet another complaint of "why haven't the operators done enough of this yet?"
Accessibility is the degree to which a product or service can be used by people with various disabilities, including auditory, visual, and tactile. Not only is good accessibility the right thing to do (as practical), but it can also make a company quite a bit of money. The U.S. Telecommunications Act specifies that the federal government must purchase accessible options for telecommunications equipment.
As local governments tend to adopt federal government practices, this means that 25% of the U.S. adult population could be covered by this purchasing practice.?? European regulations are similar in scope. Yet the big players (Nokia excepted) are ignoring the market and regulatory implications.
Besides, lots of accessibility practices have non-disabled markets available. Wouldn't you like the ability, at least sometimes, to use your entire phone by voice?
The current state of affairs is pretty poor. Nokia, in general, is the leader. They've had hearing aid interfaces for at least some phones for a decade or so. The fact that their devices run the same software plus their huge market share (at least out of North America) makes them a good target for developing software solutions. Indeed, Code Factory's mobile Accessibility is a Symbian solution to make many phone functions hearable with a voice synthesizer. The page's Spanglish is such that I'm not sure whether there is voice input or not.
The American Foundation for the Blind's technology magazine helps readers navigate the array of technology usable by those with vision impairments, though be sure to search for "cell" not "mobile". A review of mobile phone options gives you some of the lay of the land. They also compare cell phone reader software, which will go a long way to making mobile web sites potentially accessible.
Hard of hearing users are not being left out. While text pagers and Blackberries have long been wonderful tools for deaf users on the go, WGBH is extending its closed captioning technology to mobile media. Expect this to take a few years to pan out.