Instadesk
This cool desktop apps allows you to do everything you can do with Instagram, except upload photos. Unlike most services, it even lets you organize your photos into albums.

Carousel
Feeling minimalist? Try Carousel. It's more compact and sticks to the basic Instagram features.

Instagrid
If you want to check Instagram on the go, Instagrid provides a simple web service to do so. For another similar alternative, check out Inkstagram.

Statigram
Statigram is a full-featured Instagram statistics aggregator. Use it to check out stats like what your most liked photos are, and what filters you use the most.

Printstagram
Instagram photos are so much better when you can use them in real life. Make posters, stickers, prints, and mini-books easily through Printstagram. The service is relatively affordable for what it offers. For example, you can get over $200 stickers for only $10.

Casetagram
Casetagram is a fun new service that lets you design an iPhone case featuring your Instagram photos. It's totally customizable and only $34.95.