Pull To Refresh Safari is a new tweak that adds a new feature in Safari Browser. The tweak adds an interface very similar to that found in most twitter clients and official Facebook app.
It allows you to refresh the page in Safari by pulling down the page. This tweak is available via Cydia Store. So it means that first you have to jailbreak your iPhone to get access to Cydia Store.
Find the complete step by step procedure here to jailbreak your iPhone. After your iPhone is jailbroken, launch Cydia, refresh Changes and search “Pull to Refresh Safari” to install it.
This app is free of cost and it requires iOS 3.0 or above and it also needs Mobile Substrate to run.