Spy

Spy OS X (for Mac OS 10.1.5 and up) allows you to run a small server on your Mac, that when accessed by any normal web browser, allows people to see your screen, as well as information about your Macintosh. But it doesn't stop there - they can look at a normal static image, or they can look at your screen, live, in real-time. You can also choose which image format you want to use - JPEG or PNG. Not only that, but the user can choose what picture quality they want by manually specifying their desired quality and scale in the picture.jpg or picture.png request. Other features include 2 built-in layouts and custom layout support, and a Live Connection manager that lets you see everyone that is viewing your desktop live as well as disconnect any of those users. Best of all, Spy is totally free. Spy v1.0.1 lets you turn off Live, limit the number of people who can view Live, and has several other small changes.