Are you mean CreateTagged PDF on pdf export option?
I don't think that is the same. To create an Accessible PDF (with tags placed into it) you Export to PDF for Print, and then select "Accessible PDF" in the first option called Adobe PDF Preset. It's in this second step under the Presets that the Accessible PDF option is not showing up. I get High Quality Print, Press Quality, Smallest File size, etc.
There has never been a PDF preset called "Accessible PDF." I don't know where you heard that.
The good news is that you're using InDesign CS5.5 which by default adds more accessibility possibilities. But you'll still have to do things yourself. For example, accessibility requires that you are properly using paragaph and character styles consistently. It requires that you use Object > Object Export Options to set Alt tags for your images. It requires that when exporting you select Tagged PDF.
But that is not sufficient for perfect accessibility. You'll also have to use Acrobat Pro to specify the language (in File > Properties > Advanced), and it may also require that you set up the Reading Order.
There is now an excellent video series at Lynda.com about creating Accessible PDFs from InDesign or Microsoft Word. Here's the link:
You can get a free week of Lynda.com videos:
Thanks for all of the great information. Very much appreciated.
However, I did get the reference to exporting to Accessible PDF from this Adobe video:
If you go to the 2 minute mark this is where they show the step I am referring to.
Now I do see that they are using MAC so maybe that is the difference.
I've watched Michael's videos before. He has created a Custom PDF Preset (it's not built in). Starting with PDF/X-4 or High Quality Print, you can make all the choices he shows you, then click the Save Preset button at the bottom of the screen. And, if you wish, you can name it Accessible PDF. But it's not built-in.
It's a good video, but Chad's Lynda.com video goes into it into more depth.