Turn current Paypal Payment Standard method to Express Checkout (PHP)

Currently have paypal checkout php set as Standard and would like it converted to Express Checkout - so the code, and relevant reference phps, need adjusting. Would suit someone who does this kind of work regularly and has a standard code template they can implement. There is some custom php form and database stuff which goes along with the code, but I don't think you will need to adjust very much of this - At the minute the payment flow goes: 1. Form --> 2. Form verification php --> 3. Paypal Standard payment --> (then, IF THE USER PRESSES RETURN TO MERCHANT) --> 4. Form information written to database. And I would like the payment flow to go: 1. Form --> 2. Form verification php --> 3. Paypal express checkout @paypal --> 4. Confirm order ON MY SITE, which then 5. Writes form information to database. Think that covers it, may also want an IPN listener added, though my understanding is a) these are quite simple to implement and b) if the new form payment flow works properly and database information goes in properly, IPN won't be essential.