IPNetMonitorX recognizes the GetURL ('GURL') AppleEvent to support URLs of the following form:
Copy any of these URLs to your web browser (or click on them) to get a feel for how they work. When you copy and paste the entire output from a tool, the first line is the URL used to run the corresponding query. Thus you can save specific queries you might use again in any URL bookmark manager, document them on web pages, or share them via email.
Many of the elements in these URLs are optional and will use a corresponding default if omitted.
The general syntax for URLs is described in RFC 1808. Unfortunately, some applications like the Apple Help Viewer truncate valid URLs causing any URL parameters to be ignored. Others like OmniWeb and Safari do not recognize this newer standard and do not pass unknown URLs to Launch Services so they can be directed to the corresponding application. I expect these problems to be addressed over time.
In some cases, Launch Services may not be configured to launch the desired application. In this case, you can use the More Internet Preferences panel http://www.monkeyfood.com/software/moreInternet/ to examine or change the mapping of URL schemes to helper applications. Alternatively, you can examine ~/library/preferences/com.apple.LaunchServices.plist to remove the previous mapping and then launch the desired application to register a new one.