There is a fast and easy way to add captions to your images in Aperture 3. And I show you how in this video tutorial that's also part of my Aperture 3 Essential Training on Lynda.com.
I think the best time to add captions is right after you upload the images. That way the information that accompanies the images is still fresh in your mind.
More Aperture Tips and Techniques
To learn more about Aperture 3, check out my Aperture 3 Essential Training on Lynda.com. Also, take a look at our Aperture 3 Focus Section. Tons of free content about how to get the most out of Aperture.