I have an existing shopping cart I programmed in PHP that currently integrates with PayPal. I'd like to also have an option for accepting Bitcoins using a leading bitcoin merchant service like BitPay or MtGox.
I have only have only 3 prices that items cost so fixed buttons can be used.
The confirmation page I use to send the details to PayPal will have a link to the PHP file you create for me.
I will pass the following variables:
1. A unique identifier - order number
2. The price of the item (1 of 3 values in USD)
3. The customer name, address, and email address.
Using one of the leading Bitcoin merchant services you will call their API to determine the current USD to BTC conversion rate and then provide the customer with a bitcoin payment address. Depending on the capabilities of the merchant services you will also display the details of the order as I've passed to you.
Once payment is received the merchant will have to send an Instant Payment Notification (IPN) to a PHP form you'll create. This second PHP page will accept the notification and will update a MY-SQL table to show the status of the order as paid.
At the completion of this project all ownership and rights of the code will becoming mine. All work will be completed in PHP and no compiled code will be required.