You can make a video slideshow of your favorite Instagram photos in under a minute with Flipagram.

Flipagram by Flipagram LLC for for iOS, $.99/£.69 

Compatible with iPhone 3GS and later, iPod touch (3rd generation) and later, and iPad. Requires iOS 4.3 or later. 

Once you've logged in with your Instagram account, it's easy to use Flipagram to create video slideshows of your Instagram photos for selective sharing on your iOS device or via email, Facebook or YouTube. I was able to create my first Flipagram using images from a Montana roatrip this summer in under a minute.

Just select your favorite Instagram images ...
 ... pick a title and other options, and you've got your first Flipagram.

Tap the Create button to view all your Instagram images and select those you'd like to use in your slideshow by tapping them, then tap the Next button. The Sort screen will let you decide which order to display your images, tap Next when you're satisfied with the arrangement. You'll choose a title, slideshow speed, add audio from your iTunes library and more options on the Refine screen, then tap Finish to create an mp4 file. Tap the Share icon to save your video slideshow, or share it.