Square Up from Square Inc – A payment processor who specialises in mobile payments on Iphone (IOS), Android and other smart phones. The will send you a mobile card reader for free which judging by the pic just plugs into the phone allowing you to swipe cards and take payments on the spot, perfect for trade shows/markets and the like. The fees seem low at 2.75% per swipe and nothing else on top and with next day deposits it seems good.
Stripe.com – “Payments for developers” is a web based payment gateway system for developers of ecommerce sites and any other sites that require a gateway adding on. There service is more geared towards a programmer making sites or web apps for someone. They have a API thats available in different languages. They offer direct payment of transactions into your bank account so thats a plus.
Found a interesting post comparing PayPal and Amazon Payments, its a short list but shows some major points.