Opulos NuZip
Create password protected zip files from the Send To menu.
...Copy NuZip.exe and Ionic.Zip.dll to the desired folder (e.g. C:\Program Files\Opulos\NuZip\).
2. Double-click NuZip.exe. This will create a new shortcut in the Send To folder, which appears as a new menu option in windows.
3. Done.
NuZip is written in C# and targets the .NET35 Client Profile.