With the release of AutoCAD 2011 we replaced the CHM (compiled HTML) based Help system with an online browser based HTML based Help system which you can set to default to online or offline mode and also select your browser of choice.
Based on customer feedback, the search performance is not equal to that of the old Help system at this time so we are providing the CHM files for download. It is a 172MB download and currently will not work on 64bit Windows 7.
We will be working to improve the current AutoCAD 2011 online Help to improve the search capabilities as well as add new features to the new online Help.
AutoCAD 2011 Help in PDF format
Also check out and participate in the AutoCAD Wiki based Help Beta
AutoCAD Wiki Help Beta
Cheers,
Shaan