Initially Instagram was devoted to mobiles only, but now you can see the working version of your Instagram feed online. Just visit instagram.com and log in to your account. After that you can browse the recent pics of people you follow with latest updates, if you want you may like a picture by double clicking or using the like button, then you can leave comments, follow/unfollow people. In fact, it works almost the same as on your phone.
But the service has a serious disadvantage — you can't upload pictures.
Picture credit: cnn.com