Instapaper is a great app. I bought the paid version a few months ago. Every time I find some interesting article or blog post I save it to "Read it later" in Safari so that I can read it when its convenient for me. There are primarily three things I particularly like about the app.

1. Instapaper does not simply bookmark a page for you and show it to you later. It rather saves the page and formats it in a manner that makes it very suitable for reading in an iPhone. This means that the page is convenient to read (As you can judge form the screenshots below) and you can read those articles/blog posts offline.

2. Another amazing feature of the app is "tilt-scrolling". Click on the tilt-scrolling button in a the toolbar and if you tilt the iphone to the back, the page automatically scrolls down, tilt it forwards the back scrolls back up. The more you tilt the iphone the faster the page scrolls.

3. I can save pages directly to my Instapaper account from everywhere. From Firefox, from the iPhone Safari and Mac Safari, all saved pages are accessible and can be organised from the Instapaper.com site.

This is an app I'm glad to have purchased! Its worth every penny. You can get it from here.