vbulletin and Joomla: same theme?

[RC CHOP]

Hey folks,
I'm the current webmaster and co-leader for an online gaming clan called Rogue Cell. Anyways, I am currently implementing Joomla as our main CMS and vbulletin as our bulletin boards. The 2 systems have separate databases, to ensure some site stability. Here is what I am trying to do. I want to have Jomla as our main site that pops up on a visit and then have the forums as a menu option. Now instead of loading the vbulletin within the wrapper (an iframe), which I am currently doing, I want to load the vbulletin with the Joomla menu and header. I want the site to basically look like it has the same header but loads the 2 "sites" and passes very minimal info back and forth. For instance, I want the header for Joomla to have a login and create the session/cookie for being logged into the site. That way I could then call info from the vbulletin db and show it in the joomla section if desired.

Anyone have any suggestions on how to do this efficiently? I'm somewhat decent in php and html and css, but I am no expert. I guess I am basically looking for some help finding the code to write to put in and where. Once I get all of that stuff running, theoretically, I should be able to use some styling from the vbulletin in the Joomla area as well.

Thanks in advance to any advice or help given. : )

http://www.theroguecell.com
Joomla! v1.0.13
vbulletin v3.6.8PL2
web hosting: Yahoo Small Business
Server Type: FreeBSD
Web Server: Apache v1.3.33 (cgi-fcgi)
PHP: 4.3.11