Hi Jo,

Yes, pasarelas are gateways, and micropagos is micropayment. It refers to payments involving small amounts of money.

MilliCent es un sistema de micropagos desarrollado por los equipos de investigación de DEC en 1995 como una alternativa económica, flexible y eficiente a los sistemas de pago con tarjeta, cuyo coste resulta demasiado elevado para transacciones de bajo valor.
http://www.iec.csic.es/criptonomicon/comercio/micropagos.htm...

As a software development group specializing in smart card technology, micropayment systems, payment gateways, and hardware development, Infinit-E is regarded as an indispensable Mondex Card enabler for the US-based projects.
(http://www.infinit-e.net/news/)

Micropayment
Whether it's a payment of 50 dollars or 50 cents, ClickPay will process your order and wire the funds into your existing bank account.
(http://www.multiactive.com/smbiz/ecbuilder/clickpay.html)

Hope it helps.
Cindy