Is there a way to create text in a circular shape with a text flow like in InDesign text boxes?
This is a great question (and kudos to Donna for also including an image in her email which made it easy to understand what she was asking for), as it exploits one of the strengths of Type on a Path in Illustrator -- which is that Path Text objects can be threaded. If you're unfamiliar with the differences between Point Type and Area Type in Illustrator, refer to this post. Since Illustrator CS, when the newer text engine was introduced, Type on a Path in Illustrator acts like Area Type - and can be threaded just like text frames can be threaded in InDesign.
Rather than try to explain to Donna how to perform the technique she was after, I recorded a quick video, which you can view below. You can also download a full-res version of the video here.
Illustrator Type on Path Tutorial from Mordy Golding on Vimeo.