on the Desktop Search pages.

For instance on their FEATURES page ( http://desktop.google.com/features.html ) it explains this caching and also explains how to REMOVE cached pages (click the "Removing Results" link at the top of that page) and within that portion of the page it explains how to set your preferences to avoid caching.

Reading the FINE manual is a good way to answer most questions about a program's FEATURES and functions.