Installation

Installation should be fairly easy for a user somewhat comfortable with regedit.

Normal registry warning: If you aren't comfortable with regedit, or you don't understand these instructions, don't try it.  Altering your registry can make your computer behave improperly, or become unusable. This script is provided as-is with no guarantee or promises of fitness. Follow these instructions at your own risk. And so on.
  1. Save this document on your local machine. (for this example, we'll say c:\followup\followup.htm)
  2. Add the registry key: [HKCU\Software\Microsoft\Internet Explorer\MenuExt\Followup Url]
  3. Set that key's default value to the uri where you saved this file (like file://c:/followup/followup.htm)
  4. Add a DWORD value to the key named "Contexts". Set its value to 0x20 (32 in decimal)
From here on out, anytime you right-click on a URL in explorer, the context menu will have an additional entry: "Followup Url". Clicking this will create a new task in outlook for followup and display outlook's new task window to you.

Removal

Removal is even easier:
  1. Delete the registry key [HKCU\Software\Microsoft\Internet Explorer\MenuExt\Followup Url]
  2. (Optional) delete this file.