This page is very blah and plain, but it demonstrates how frames look. The two smaller frames on the left can currently be resized by the visitor (that's you!), but that can easily be turned off.

Typically, the smaller window in the top left can be used to display information that changes rapidly. This can be a shopping cart, sports scores, stock ticker, calendar, or something else along those lines.

The bottom frame on the left is usually used to hold things that do not change often. This is typically a navigation bar or some other form of information.

The main window (where this text is currently at is usually used to show the main content of each page after a link is clicked.

This page is an example of three frames, but frames can be layed out in almost any imaginable combination and style. If a website does not require frames for easy navigation or use, then I would highly suggest that frames be avoided. Some older web browsers cannot properly display frames and sometimes users get confused or frustrated when frames are used.