On Crashed The Wedding, there is a part you will need a password for - the password is WEDDING.
On You Said No, the same thing applies for this, but all it does is lets you print of a personalised signed picture of the boys. Since it's personalised, everyone got their own passwords. These were sent by email to all people who were signed up backstage at busted.com by the end of March 2003. I think they are the same as your number which you receive when you sign up, so try using that.
Each of the CDs from the first Busted album has a code on it, which you may or may not have noticed. They are made up of a sequence of numbers, and you can work out what they mean by counting it as 1 = a, 2 = b, 3 = c, etc etc. If you can't be bothered to work them out, here's what they all say:-
Busted album - 'welcome to our first album!'
What I Go To School For - 'busted debut single'
Year 3000 - 'we are not numbers, we are free men'
You Said No - 'here's single three...'
Sleeping With The Light On - 'has anyone got a candle?'