You can easily add a night vision effect effect to a photo using the free NightVision Photoshop plugin offered by VanDerLee. The plugin can also be used to produce images that look like they were taken by a security camera or to apply TV scan lines.
You can read a bit more about how to install plugins if you're new to this method of extending software.
While this Night Vision plugin has been produced for Photoshop, you don't have to have a copy of Photoshop to use the plugin. There are a number of graphics editors that can use plugins with the .8bf file extension and the screen shots for this article show the plugin used in Irfanview.