Moving blog to root and 301's

I want to move my blog from it’s current location in /blog to the root. I’ve read up on this and it seems easy enough, I also read I can leave the blog in /blog and just move a few wordpress files to run the blog from the root directory. All sounds easy enough.

My question is how do I set up 301 redirects so all my links from Google and other websites still work properly? Is there a line of code I can use in my htaccess file to do this?

Also which is the better solution, moving wordpress in its entirety to the root or leaving it in the /blog folder and just moving the files required to run from the root – I presume doing this would give duplicate content if I’m not careful?