I have become fascinated with scraping content off of Instagram mainly for curiosity and helping my wife analyze her competitors pages in terms of hashtags, ranking, and image placement, times posted, etc. I was certain something had been written for this before that was free, but it seems like there are bits and pieces out there in python, php, and a variety of other languages. Not to mention many paid solutions. I stumbled into a piece on github: https://gist.github.com/cosmocatalano/4544576 and decided to improve this a bit more. The modified version I shared here and on GitHub includes collecting the post code, likes on 10 most recent photos, and number of comments, in addition to keeping tabs on follower count. I run this on a small LAMP setup and have it run daily. Check out the modified version on GitHub.
For those wanting to make changes to this, check out http://www.jsoneditoronline.org/ it makes it much easier to read through all the JSON fields and zero in on the fields you want.