There's probably a better way (you could probably do it with an htaccess edit only) but what I'd do (if I couldn;t be bothered googling better way) is create a new php file as gymph said in post
#393 and call it myhome.php and put it in your forum root
Next edit your .htaccess file in your forum root and add a line:
Code:
DirectoryIndex myhome.php index.html index.htm index.php index.cgi index.pl default.htm
Now when someone visits your forum root (with out explicitly enterting a filename to access) it will defualt to myhome.php which redirects to whatever page you specified in the phpfile