Apple announced last week that they will be releasing iOS 6 sometime this Fall. There have been quite a few additions and changes that were mentioned (and some that were not) and I thought I'd share some of them here.
Voiceover changes - one of the big drawbacks to using Voiceover was that you couldn't use it with Zoom and/or Assistive Touch so you'd have to pick what you like to use. That is changing with iOS 6. Now Voiceover will work with them so you can use them all as you use the device.
Speak Selection - a little known feature of iOS 5 is called "Speak Selection", located in the Settings - General - Accessibility, once on you can highlight text and you will get an option to have it spoken to you. This works in most parts of the OS and is most helpful when using mobile Safari. In iOS 6 it will have the addiditonal feature of highlighting the words as it speaks them.
Siri Improvements - many of the improvements in Siri are related to finding more information, but one is a big change. Siri will now give you to option to launch apps (not sure if it's all apps or just the standard Apple apps), making these devices even easier to operate.
Guided Access - This new feature add a few different capabilities. It gives you the option of disabling the Home Button so you have to stay in the current app. This could be very useful for a person using the device as a communication tool. It also allows you to block off certain portions of the screen (like settings buttons or ads) to keep individuals from accessing them. I haven't seen how it will work exactly, but during the keynote they mentioned it was as easy as drawing a circle around the screen.
There are a few more announced and unannounced changes, you can find all of them here at Apple's website. You can also find some more info about the accessibility features at Luis Perez's Blog.