How do I buy apps on Android market from my phone?

I've gone onto Android marketplace and it gives me the option to put my card details in. Somewhere else I read about Google Checkout - which I think is like PayPal? What's the best way of buying apps through the Android marketplace?

I'm used to Apple and iTunes etc and am new to the world of Android! (But loving my Galaxy S2!)

Thanks for your help in advance!

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia…).