URL Redirection

[no_sprinkles]

PHP Noob here, so please pardon me if my question sounds stupid

I have a website www.mysite.com and a subdomain of that website www.forum.mysite.com
For some weird reason forum.mysite.com seems to attract a ton of visitors who bypass "mysite.com" to access the site. I would now like to make "forum" a directory under "mysite" like so: www.mysite.com/forum and want folks to update their bookmarks to point to the new site.

I want folks who access the old www.forum.mysite.com to be redirected to "www.mysite.com/forums". The only catch is I would like visitors to wait for five seconds at "www.mysite.com" before they are forwarded to "www.mysite.com/forums"

Obviously a simple header(Location: url) won't cut it.

My question is, should I simply redirect visitors to "www.mysite.com" from the old "forums" subdomain. Then have "mysite.com" recognize the url that forwarded my visitor, wait for five seconds and redirect the visitor to "mysite/forums"?
This seems a little inelegant to me. Is there a better way of accomplishing what I want?

I would appreciate any help or pointers in the right direction.
Thanks in advance.

[Velox Letum]

<meta http-equiv="refresh" content="3;url=http://new.url.com/">

Alternatively, you could use the php sleep() function, then after it's done sleeping, output the header...