If you have a Mac, you've used Expose. MouseposÈ is something similar, except that its purpose is to show you (or someone you're demonstrating something to) where the mouse pointer is. Or more properly, an area of focus around the mouse pointer.

This is great for demonstrations, explanations or when you've lost the mouse cursor yourself :-) It also reduces the number of smudged fingerprints on your screen.

MouseposÈ is free (with a free registration required) and is available at Boinx Software.