Yes. There's a ton of them, though. I'd recommend you to the Adobe Website, read the new features for ID CS and then bring specific questions back here.
Some of the significant new features are: separation and flattener preview, story editor, nested styles, pathfinder, customizeable stroke styles, customizeable underline and strikethrough, support for mixed ink swatches (device-n), support for PDF 1.4 and 1.5 formats for import, support for PDF/X for expor, support for exporting interactice PDF with sound, movies, rollover and mouse-down effects for buttons, AND the addition of user definable slug and bleed areas outside the document that are understood by printing and PDF export functions...to name a few...