One finger scrolling on a MacBook touchpad

I would recommend using BetterTouch Tool with configs as shown in the img:

This will scroll the page up with single finger tap on top right corner and scroll down with single finger tap on bottom right corner

I created a free app called Scroll that allows one finger scrolling on Mac trackpads that you can download here.

UPDATE: I've released Scroll 2 that is no longer free, but includes many improvements.

• Scroll no longer needs to be the frontmost application to prevent the cursor from moving.
• Inertia scroll has been added for the modifier key and edge scroll zone gestures.
• Direction of scroll can now be configured for all gestures.
• Modifier keys can be configured within the app for all trackpad gestures.
• The modifier key scroll can now scroll horizontally as well.
• The app can also limit scrolling on the Magic Mouse (not related to this question)

Version 1 is still available for free on the website.