Curly,

Many of us here use Melodyne for audio editing. It comes in several versions, with prices that rise as features increase.

The advantage of buying a 3rd party product is that it is portable to other music programs. Features that are built-in to a product are like the slogan "What happens in Vegas stays in Vegas"

As stated already, there are lots of pitch correction products available, but I like melodyne for these reasons:

1) it works the same way as a midi piano roll editor, which is a concept many of us already understand

2) you can fix other problems besides pitch. Just like a piano roll editor, you can stretch notes to change duration, drag notes to change timing etc

3) you can use it to add audio harmonies to your played part.

4) you can even change the subtleties of transitions between notes

here's a link in case you want to read more or watch demo videos:
http://www.celemony.com/cms/

https://www.dropbox.com/sh/ey71h8ep047758h/AAC12jNM0Hz9Q8zsh5iDeqNHa?dl=0