Both Pinterest and Instagram have taken off and become very popular since their launch. Now you can use both at once on the web or your iPad with Pinstagram! The downside to Instagram is that it’s an application that you need a smartphone to use it (iPhone or Android). So, for full disclosure this site is for folks who already use Instagram, but would like to do so on the web or their iPad.
Once you’ve registered, you can login on this site and manage everything from the web. The next thing I’d recommend is checking out the FAQ  as you load right into the application with little to no explanation.
If you click Instagram on the left, a menu will drop down giving you access to the Feed, Popular, Nearby, My Photos, and My Likes. Letting you access your own and popular content via the web.
There’s another menu at the top right of the page with icons that will refresh the page, as well as the same options as under Instagram, and a settings button.
What I think this site is the most useful for is managing your feed if it has gotten out of hand and you need to see multiple images at a time. It also allows you to easily share your images on Pinterest by clicking the heart button. This will bring up a pin that you’d fill out like anything else you pin.
If you use Instagram, give it a try!