Couple Problems

Hey Guys,

I'm new to the forums and just had a couple questions for you. I have been playing guitar on and off for the past 4 years and have finally decided its time to really kick up my playing. I seem to have to issues that keep me from playing better though.

#1- Infrequent use of my pinky and having a tendency to use my fingers in the wrong spots. Its an old habit that is dying very hard! Does anybody have any exercises that can help to strengthen my pinky and help to keep my fingers in line?

#2- I read somewhere in the lessons that if you want to play fast then you should keep your thumb on the back of the neck. I tend to bring my thumb around to the side when I am playing though, again from old habits, has anyone else had this problem? Its so hard for me to learn the new way!

Thats pretty much it for now, I have been working really hard to try to correct them, but any help or advice would be aprreciated!