The following doesn't need too much PHP knowledge, providing you know some basic PHP and how to work with MySQL (basic too xP) and variables.
That little file called global.php is very important. Just put in a require command anywhere, usually at the top, of a PHP doc and it'll automatically open up all vB variables and functions to you. From there you can use $bbuserinfo[username] stuff and all the rest.
An easier solution would be to use a hack already released here at vB.org. I'm in a rush at the moment but there's several hacks that allow you to run any webpage via vBulletin; just search around.