Ecommerce Solutions for Office Live

Paypal-Payment Gateway

Paypal is a excellent, safe, and secure way to accept payments.  Which is required for several of the other payment gateways as well.

Google Checkout-Payment Gateway

While not as popular as Paypal yet, offers some of the same features.  If you need a shopping cart, you will need a thrid party shopping car.

PayLoadz

A excellent service if you want to sell digital goods such as e-books, downloadable software, ect.