I am developing a website and I need to receive payments from PayPal and Credit Card, the thing is that I know nothing about this, and my question is where I can find some great resources to help me, or if you have some example codes, everything that can help me.
Thank's alot.
If you're planning on Paypal integration you'll find Paypal's Sandbox a vital tool;
https://developer.paypal.com/
As this sort of thing can be a chore and you'll probably end up using Paypal's IPN service (Instant Payment Notification) anyway, I'd do a search for "Paypal IPN class" and save yourself some development time.
PS I don't know whether IPN is specific to a particular Paypal solution (ie Payments Pro) or if it's relevant to all Paypal solutions, if someone who knows could edit/update/comment then I'd be very grateful.
Create an account at paypal. Then you will have access to its webbased API's. It ships with decent documentation and support.
The same story applies to other decent credit card companies: just have an account and ask/look for its webbased API's. Your webapplication has just to call those API's.
You will need to acquire a Merchant Account in order to process payments via Credit Card. These companies typically charge a percentage per sale. I cannot recommend you one at this time.
As for PayPal, there are free and paid services through them as well. You can use PayPal as your merchant account as well, I think I recall. (Correct me if I am wrong).
Regardless, a project like this will require a lot of reading, and testing by your part. Dealing with online transactions such as this, is an amazingly rewarding experience.
PayPal just launched a brand new developer website at https://www.x.com/