Start with the free stuff and go from there. Windows Live Movie Maker is free and will handle high res video easily. If you have an ipad, iMovie is a good choice for starting off.
Once you get the feel for editing, or find the limitations, there are tons of other options only limited by your budget. I have heard of a good one from Sony, and of course Adobe has a series of products from the sub-$100 to the commercial products.
All you have is time to spend learning them. But once you do, it's pretty cool.
Quick tip: many of the entry programs have the ability to one-click upload to YouTube. I have found whenever I have done that, it defaults to a much lower resolution. Since then, I have been able to upload manually through a browser and keep my resolution and minimize compression.
I only realized that even the raw footage from my GoPro is much higher when I don't even edit it. But there is always some editing needed. I uploaded some raw footage of my buddies new lake lot, as I wanted it up quickly. That video on Youtube on a Retina Display is amazing compared to my edits!!
Good luck!
Check out my examples on my Youtube channel.
www.biff.org
