I constantly hear people talk about running out of space on their phone, and when I ask about photos, most have 1000+ on their phone. This is a waste of space, and a risk because most don't back up these photos. A lost phone can be detrimental.
I highly recommend the Flickr app, by Yahoo! - the app just received an update and will auto upload photos to a private album so the process is effortless. Flickr accounts are free, and you receive 1 TB of storage space... that's over 419,000 photos from your iPhone! If you already have a Yahoo! account, then use that same username and password to sign into the Flickr app.
These uploads can take place via Wi-Fi only or a Wi-Fi and Cellular data. Once your photos have been uploaded, simply delete them all from your device, and they're still available via Flickr on the web or via the same app. Photos are also very easy to share via Flickr. For more info on Flickr, check out their website and FAQs. This works for iPhone, iPad, and iPod Touch.
Once you're up and running, and loving Flickr, connect with me!