Pocket (formely known as Read it Later) by Idea Shower. First you need to create an account at Getpocket. Then download and install the appropriate Pocket extension for your Desktop browser. If you're using Firefox you can get the Pocket Add-on here. Install Pocket for iOS and login with your user account.
On your desktop browser there will be a small (downward facing arrow, grey-white when not saved or red-white when a page has been saved to Pocket) icon in the right end of the address bar which you can click anytime you find an article on the web that you want to save to read it later on your mobile device. The articles that you save (by clicking on the Pocket icon on your desktop browser) will automatically be synced with your smartphone once you open the Pocket App on your iOS device.