On NetTuts.com they're posted a new tutorial about using the Stripe service to accept credit cards on your site. Thanks to some handy libraries they provide, integration is a relatively simple process.

Until recently, accepting credit cards on a website was expensive and complicated. But that was before Stripe: a radically different and insanely awesome credit card processing company. Today, I’ll show you how to start accepting cards in 30 minutes or less – without spending a dime.

They step you through the whole process you'll need to get the full flow set up:

• Install an SSL Certificate (on your server)
• Create an Account
• Create Your Payment Form
• Collect The Form Values
• Request a Token
• Create a Server-Side Script

Screenshots of the Stripe interface, HTML, Javascript and PHP code are all included - everything you need to make the simple card handling work. One of the keys to how Stripe deals with credit cards is that you provide it the card info, it gives you a token. Your app uses this to work with the card instead of storing the card information in your database (also making it more secure).