[Sir_CnC]

As Jimmy said you need to know HTML CSS and PHP, also you'll have to learn how to implement your PHP, also as you'll be linking two websites together, your going to need to check the fields in your database in order for the website to gather that information, it shouldn't be to hard, just make sure that when you setup MyBB you set it the password hashing to MD5 otherwise you'll have problems logging in on your end.

For the actual website I recommend using the Twitter Bootstrap as it'll just make your life 20x easier: http://twitter.github.com/bootstrap/

Good luck with this mate, also you MUST make sure that your database connections are encrypted, and their isn't any vulnerabilities in the code.

Thanks for that link! Shall hopefully be useful for me!
As for encryption and vulnerabilities, that's on my list of to do things before release, make sure it has good encryption and look up ways on finding vulnerabilities inside of my website or getting some people to check over it for me! So far I can only check for SQLi as that's all I know how to do.