The wait is over. Instagraph, the unofficial Instagram posting client for Windows Phone 8, will be available to be downloaded in the Store within the next 12-24 hours as it has now been published.
The app does have a nominal price of $2.49 with no free trial to help support the server investment by the developers. Currently, only Windows Phone 8 is supported but Venetasoft do plan on bringing Windows Phone 7.x backing in the future (see the FAQ printed below). In addition, at least initially users will only be able to upload 3 photos a day to Instagram via the service in order to ensure that capacity is not overrun, resulting in extraordinary upload times. That number will be increased as more servers are brought online in the coming weeks.
While the status of an official Instagram app for Windows Phone remains elusive, Windows Phone 8 fans will now be able to post to their pre-existing Instagram accounts using the Instagraph client. Later, the developers plan to support Instagram account-creation through the app directly.