This is a good resource articled provided by the Web Hosting Industry Review detailing the use of the .htaccess file.  We occasionally use the .htacess method to password protect directories and also to do apache redirects for a domain.  Apache redirects seem to be one of the best methods for redirecting sites to another location for maintaining good SEO practices.  We have learned in the past that javascripting redirections can have adverse affects on SEO.  How to Use the .htaccess File