Gratuitous use of frames is a common mistake of web designers.
Many browsers do not support frames. They disrupt the flow of the website and can be difficult to anticipate where a page may appear when a link is clicked.
If you must use frames, use the tag <base target="_blank"> between <head> and </head> to assure links will open in a new window.
Check out these links to websites whose opinions about frames is self evident:
The "I Hate Frames" Frames Page
Another I Hate Frames Page
The International I Hate Frames Club
Why Frames Suck (Most of the Time)
