Can I transfer my music from my iPhone to my iTunes? If so, how?

Hi, I have a new computer and i forgot to transfer my files. My itunes library is completely empty but i have all my songs in my iPhone. Is there a way for me to transfer/save/copy the music to my computer/itunes? If so, how do i?

Also, a bonus/extra question: Whenever i download files such as mp3 files to my account, and i have the administrator account, all the other accounts in this computer has the downloaded files as well. I don't want to share my downloaded files to the other accounts in this computer, how do i change it to just being saved and downloaded to only MY account and not the other accounts as well?

Is it possible to download apps on the iPhone 3 with no data plan?

I got an iPhone third generation for Christmas that I'm excited about.

But, my parents said that it doesn't have a data plan, which, I'm not sure what that means. I know I don't get to use Internet or anything, but whatever.
So, can I download apps without a data plan?
Everything is up to date on the phone, itunes, etc, but when I click on an app, it says in bold letters "Update Required".
I can't update the thing anymore, and under that, it says in smaller letters, "This app requies iOS 4.3."

So, does it just mean I can't period, or that the iPhone 3 is out of date? Lol.

Please and thank you for answers! :]

Added (1). Well, how?

Updated apps on iPhone 4s and facebook nowdoesn't work?

I updated all apps on my iPhone 4s yesterday had never done updates before and now my Facebook app won't work (which s the only one I use all the time!) iv deleted it and reinstalled it, iv powered off and iv downloaded new apps to try kick start it and nothing! It jus appears a blank page for a few seconds and then goes back to home screen… Any ideas?!

IPhone 4S autocorrect problems?

I typed a few words in my phone and I guess it remembered them and now whenever I go to type "haha" it types "haha" because I typed that once before. And there are more examples but its really annoying and is there a way to like reset the keyboard so it doesn't remember anything I typed?

Where can I get an iPhone 4S?

I've tried Ebay, Craigslist, and Amazon… I want a white, 16GB, iPhone 4S, good condition for around $250. I don't want AT&T, or Veriozon, or anything. I want an unlocked phone from Apple that's able to connect to an cellular phone network. Where can I get one?

I have a MasterCard gift card and it won't work

I got a $50 Mastercard giftcard for the holidays, and I wanted to put it on my iPhone
5 and my Apple iD and it says it won't match my banks records? Why won't it work? The card was purchased in Texas and I'm trying to use it in Louisiana is that the problem? Why won't it work? Its also a debit card.

My iPhone 4 won't sync with itunes?

Help ME! I'm getting really tired of this. I can't get my music from my itunes onto my phone… I don't know what i'm doing wrong…

Added (1). I've figured it out! I imply needed to drag my playlists to the device haha