That is definitely something that will definitely put you ahead of the curve mate

most students applying for interns don't even have anything to show, so it definitely puts you ahead.
You'd probably want 2 or 3 more though, showing more variety of what you've got to offer, but shouldn't stop you from applying though, as you've already got something to show
edit:
Just for example as to what I showed (Which I don't have online anymore due to lack of maintenance)
written from scratch search suggestion script using core JavaScript and PHP and mySQL for the web service
Multi-country/language survey website that allowed translation of pre-existing international question (english) and answers to be translated to different languages and be used for different cultures/countries, countries could also have their own independent questions and answers... custom CMS and Administration all written in core PHP with various design patterns applied and makes good use of MVC, this was incomplete and didn't have anything for statistic analysis, so had a couple of SQL snippets for analysing survey stats
Another custom CMS written in core PHP which got into an unmaintanable state due to poor collaboration with my fellow students

completely dumped the code afterwards, but submitted it to university as course work anyways after it was almost complete, lol
the idea was a social networking for the community, along with a blog, road damage reporting, Administration for reports, blog comments, road damage analysis etc. this took 3 weeks of writing with 3 other fellow students
-Had to get the postcode for the whole town for this so found a website, it wasn't available as a web service so I wrote a parser that parsed this for me so It could be entered in the database as bulk, my fellow students actually suggested entering them one by one... MADNESS !!
Also created 3 wordpress themes and one plugin - nothing too special but showed them anyways
Couple of Web Designs in PSD that I had created
Should give you an idea