Google recently updated the iOS app for Google+, giving people the ability to instantly upload photos and videos to their Google+ accounts. The initial setup process is easy, only requiring you to opt in or out upon initial launch of the new update; there are more settings that you can tweak and customize.
You can find the Instant Upload settings under Settings in the Google+ app. Tap on "When to upload."
Here you can turn Instant Upload on or off, as well as set the preferred network for uploading both photos and videos. The default settings are Wi-Fi and mobile network for photos, and Wi-Fi only for videos. To change either of the settings, you only need to tap on the option you would like to select.
For those of us who are on a tiered data plan, or perhaps experiencing throttling on an unlimited AT&T data plan, saving all uploads for Wi-Fi only is the only way to go.
One thing worth pointing out is that in my experience with the app, photos and videos are only uploaded when you are actively using it. Meaning, if the app is closed, your photos and videos are not going to be uploaded. You have to open the app, and leave it open for the upload(s) to take place. This makes sense, since when restrictions on background data with iOS apps are in place, background uploads aren't allowed.
By default, the Google+ app will only upload new photos and videos. Located at the bottom of the Instant Upload settings screen (not pictured above) is a button to upload all photos and videos in your camera roll.
When your photos and videos are uploaded, they are set to private by default, allowing you to make public only what you want to.
Allowing Google+ to automatically upload your photos and videos to your account is a great alternative to the Photo Stream service Apple rolled out with iOS 5.