Some of the CAL packages can be accessed via the WWW using a browser, and these are marked in the table of packages by a WWW link. There's also a list of web-enabled CAL packages available. In order to run these packages inside your browser, you'll need to have the Authorware Web Player (version 7 or above) installed on your PC. If you're using Internet Explorer you will be prompted to install this player when you click on a link to a package - a "Security Warning" dialogue will appear asking: "Do you want to install and run Authorware Web Player 7?", to which you should agree, after which your browser will download the player (size 200kb) from the Macromedia website and install it automatically as a plugin to Internet Explorer.
If you're using a non-IE browser, such as Mozilla or Opera, you will be prompted to download the player to disk, after which you should run it by double-clicking the downloaded file in Windows Explorer and follow the prompts to install the plugin.
You can also download the player from the Macromedia Authorware Player Download Center.
After installing the plugin, each time you try to run a CAL package in your browser by clicking on its link, you'll get a prompt labelled "Authorware Web Player Security", asking you to give the package permission to run and to access your hard disk, which you should give as otherwise the package won't run.