www.tineye.com is another tool that is similar to how google works, one of the two will find things that the other might miss.
The best way to protect your images is how you share them, know where you are uploading to share, I use flickr they are very good about copyrights, also photobucket allows you track which websites are using the url to your images.
If you use lightroom or bridge you can embed your copyright info in your exif data (I strongly recommend it) I have lightroom set by default to attach my copyright info to every image I import, being that import is the first step to every image being copied to my computer my info is automatically embedded every single time and I don't have to be concerned about it ever.
avoid facebook and high traffic websites where masses of people are able to view your images where they are able to right click and save them.
Recently I came across a great idea from another photographer, what he did is put a huge watermark on his photos (yes this uglifies your picture) but the watermark didn't simply say his name it stated the following "go to johndoe.com to view original image" which frankly I think is a fantastic way to direct traffic to your own website where you want your content to be viewed, where you can have your images set so "right-click-save" is disabled, great way to share images on high traffic websites ie; facebook etc.
and of course you are welcome my friends
this is the one place where I am not concerned about how I share my images and where also I feel obliged to share any amount of helpful knowledge I can