WordPress has a handy function, wp_redirect(), for sending a user to a different page. It’s an easier way to handle redirects than to invoce the header() function on your own.
To do a 301 redirect, it’s as simple as this:
wp_redirect('http://www.example.com/', 301);
Just make sure that the function is called before any output is sent to the browser, otherwise you will get a “headers already sent” error.
It’s a bit easier than the normal way to go about redirecting:
header("HTTP/1.1 301 Moved Permanently");
header("Location: http://www.example.com/");
The 301-type redirect means that the URL that the request is being forwarded to is the “real” URL, and that the client should recognize that. A 302, the default for both methods, is less preferable, designating a “temporary” redirect. Generally you should use a 301.