How can I activate PayPal In-Context Express Checkout?
Response:
You can download instructions, with screenshots, here: https://www.nexternal.com/ecommerce/Nexternal_PayPal_In-Context_Express_Checkout_SetUp.pdf The Paypal interface may have changed and no longer match this document exactly. If so, please contact Paypal Support if you need assistance.
Also, there's a great blog post about this here: http://ecommerce-blog.nexternal.com/streamline-the-checkout-process-with-paypal-in-context-express-checkout/