There was a time when Illustrator was for drawing and InDesign was for page layout. In fact, I used to tell my students that if they understood Illustrator, they would understand InDesign, and it's true. InDesign is essentially Illustrator expanded. And it is expanded quite a bit! But Illustrator has grown a lot since its invention, and has added a lot of page layout features, like style sheets, linking images, and multiple pages. So, as much as I hate to say it, InDesign just isn't worth the trouble for most of my clients. Sure, if you are doing large documents, or catalogs, it makes sense. But for brochures, ads, and most page layout functions, Adobe Illustrator can do it, and is much, much, easier.
My background is in page layout and I've always said that you should learn the correct tool for the job. A decade ago, using Adobe Illustrator for page layout instead of InDesign would have been a serious mistake. Now it's the best way to go.
If you would like to get personal on-site software training in Adobe Photoshop, Illustrator or Dreamweaver in the greater Phoenix, Arizona area, please contact me. Paypal accepted, morning appointments only.