After seeing the
recent hint about browsing local disks to view html help files with a web browser, I'd like to suggest that readers could go a step further by turning one of the excellent free browsers available for OS X into a dedicated help viewer. I've started doing this with Navigator / Chimera / Camino, so that I have a way to prevent HTML help (like that provided for most Adobe apps) from hijacking my default browser. I've done this by seeking out the index pages of the help docs I want to include, and bookmarking them in Camino. Note that some of these pages are hidden inside application packages and you may not be able to access them by navigating with the browser. In these cases, you will need to Control-click on the package in the Finder, choose 'Open Package Contents' from the contextual menu, locate the required help page, and drag it manually into the browser window. If the business of hunting down the help pages for yourself is too intimidating, simply make the browser you've selected as your help viewer the default browser temporarily, launch each of the apps whose help you want to include, call up the help, and bookmark the page when the browser comes to the front.
An alternative to simply bookmarking help pages is to create your own HTML page with links to the desired help, and make that the browser's default home page. This is what I've done with Camino and it works really well. Using a browser in this way allows you to fine tune window size and other display settings specifically for viewing help files; your default browser can be left the way you like it for browsing the web, and won't have it's 'history' bloated by the dozens of help pages you were looking at while you tried to track down the key combo for creating perspective distortions in Illustrator.
Some help files intended for viewing in Apple's hideously sluggish Help Viewer can also be viewed like this, but may not function correctly. For the record, my Camino personalised help viewer links me to help files for Illustrator, InDesign, Photoshop, LiveMotion, Revolution, Snak and File Buddy, with additional links and bookmarks that lead directly to specific sections of the help docs. Go for it. It's a cinch to set up, and a lot nicer than forcing your default browser to moonlight as a help viewer.