I am going to assume here that you are a star programmer and that all you need to know is PHP and ASP syntax. If you have never had experiances with big projects in other object oriented languages, then you're in some deeper shit...
But as a professional PHP programmer (I just got hired after my internship... how cool is that
) I can recommend Sams Teach Yourself PHP in 24 Hours to get your bearings in PHP.
It helped me... and after that: practise, practise, practise...