How to load songs from iTouch into iTunes??

I'm a total novice at the whole iTunes world. Just got a new 3rd gen. touch.
I've been loading itunes w/ songs I saved on dvd & then putting them into my iTouch & it worked, But 2 things:

After I close & then re-open itunes, I'm not seeing the songs I *thought* I'd loaded in my itune library & I'm not seeing an itunes/ ipod icon in My Computer.

What to do?