Open your image (this is just an sample image from Google):
Select the Shape tool (or press U) and use this settings:
Draw a shape where your text should go (this has to go over the image wich has to wrap te text):
Then select the Circle Shape tool and use these settings. Make sure you select the option in the right circle. This one makes the new shape to cut out of the existing one.
Create a circle in your image. The shape should cover the part of the image where you don't want the text to go. This can be every shape you want, but foor this ball, the circle shape if the best:
Select the text tool (or press T) and move your mouse over the shape. You'll see the cursor change in an T with a circle around it. This means that you can use the Shape as a textfield.
If you click in the shape you'll see something like this:
Enter your text and you'll see the text wraps nicely around the image!