paypal confusion - need some clarification

I'm a bit confused about using paypal for checkout. In my shopping cart, I am using Paypal IPN which takes me to paypal's secure site for payment. This is all well and good. When I get to the paypal's site, it presents me with 2 choices before transferring payment- login or register. I read on Paypal's website that with some kind of module, I am able to get CC payment from users who are not registered with Paypal. This is what I would like to achieve. Looks like Paypal IPN is not for that purpose. What is that module that lets me do that?

What does IPN stand for in Paypal IPN?

Lastly, as far as I understand, using paypal to receive payments via CC and debit cards sounds like a very good option to me. If I decide to use this, then I will not need to create any merchant account with a bank and also I will not need to setup payment gateways like authorize.net. So what are the pros and cons of relying solely on paypal?

This is my first time trying to setup a shopping cart. So I am a bit confused about choosing a right option. I hope some of you can guide me to the right direction.

Thank you
Ben

You need to turn on NO account required in web payment options at https://www.paypal.com

chillout_buddha:

What does IPN stand for in Paypal IPN?Instant Payment Notification, i.e. getting a message back to Zen Cart from Paypal to tell you about the payment.

Specific pros and cons would be:

pros:

easy to set up (especially in Zen Cart)
relatively low cost and no up front fees or monthly charges
accepts a wide variety of cards
well-known name

cons:

the customer actually leaves your site to deal with a 3rd party
rumoured that in the event of problems e.g. fraud attempts against you, paypal can be difficult to deal with e.g. holding back your funds to protect themselves - but I have not experienced this personally.