Picasa web and Google+ are the products provided by Google Inc. Google integrated Picasa Web into Google+. When you access your Picasa web account, you will automatically get directed to Google+. Google+ has a feature "Auto Backup" which allows you to automatically backup photos and videos to Google+ account from your iPhone. By default, Auto Backup is set to backup at full size. You can backup unlimited number of standard size photos and videos. It allows you to backup videos less than 15 minutes and having 1080p resolution or less. If you are looking for a step by step process to backup videos from iPhone to Picasa web or Google+ account, read below.
You can install PicBackMan's Picasa uploader for Mac from the website and start backing up photos and videos.