I think what you are referring to are Illustrator's "art boards".
All artboards in a document share the same media type format, such as Print. You can print each artboard individually, tiled, or combined into one page. If you save a multiple-artboard Illustrator document to a previous version of Illustrator, such as CS3, you can choose to save each artboard as a separate file, along with a master file that includes all artboards merged.
Illustrator CS4 allowed you to save artboards as separate files only when downsaved, but in Illustrator CS5, you can save individual artboards for current versions as well. The options to save each artboard as a separate .ai file is available in the Illustrator Options dialog box.
You can preview artboards from the print dialog box before printing them. The print settings you choose are applied to all of the artboards you selected to print.
By default all artwork is cropped to an artboard and all artboards print as individual pages. Use the Range option in the Print dialog box to print specific pages, select Ignore Artboards and specify placement options to combine all art onto a single page or tile the artwork as desired.
In Illustrator CS5, artboards in a document can automatically rotate to print to the chosen media size. Select the Auto-Rotate check box in the Print dialog box to set auto rotation for Illustrator documents. For a document created in CS5, Auto-Rotate is enabled by default.
For example, consider a document with both landscape (width is more than height) and portrait (height is more than width) media size. If you select the paper size as portrait in the Size of the Print dialog box, then the landscape artboards automatically rotate to portrait media when printing.