Hi all experts and veterans, I am a totally new iPhone user (2 days old) 
A few noob questions to ask, wish someone will guide me on the transition from long time Nokia to iPhone user... 

[1]
Got my iPhone 3GS (16GB) from Maxis.
Does it mean my phone isn't locked?
So what's the different between Locked and Unlocked?
[2]
I launch an application, then how do I close/exit/quit an application?
I always press the (HOME) button after using an application.
For example: I open Safari to browse the web, when I want to compose an SMS,
I press the (HOME) button to go to the main screen then tap and "Messages" icon.
Then what about Safari at the background? How do I exit the application?  
[3]
While I am at home, I use my Wifi to go online (on my router).
However, for security reason, the Wireless SSID Broadcast was set to Disabled on my router.
I can manually enter the SSID and password to "Join" the WLAN network.
But the next time when I want to use the Wifi network again, I will have to manually enter the information again.
The phone did not save my WLAN information, is this normal?
[4]
What is the benefits of Jailbreaking the phone?
I think I only have those questions at the moment. 
Thank you!  

Sorry if this has been asked before.
A few days ago, I updated the carrier file (digi) from iTunes.
Yesterday, I noticed that there was Internet Tethering option under Network.
At first, I was YAY, now I can tether with digi instead of only Maxis.
Last nite while playing game on the phone, I noticed I had ads running which was not supposed to without connection which I ignored.
This morning, I got a shock, as it seems that there is no Cellular Data Network option --> meaning I cannot set my APN hence unable to disable edge.
Can anyone help me?

@crazy25kid
Am having the same problem. After update the digi setting via itunes. When i call digi on how to undo it, they said must restore..!!

i have a question here...does anyone of u heard or experienced before that the iPhone cracked itself?
i signed with maxis, maxis says its not covered and wants me to pay 700 for it. what should i do?

Hi.. Yesterday i have done a reset to my phone at 10pm. Till now the phone still at apple mode.? How long the reset will take.? Please advice.. Tq..

@nokia2003
Thanks. How long normally will it takes.? Pls advice..

@nokia 2003
Now it shows slide to unlock and went to emergency call menu.
And says "would u like to restore ur previous backup" i press yes..
Iphone prompted restore in progress.. and iphone is activated..
am i at the right way..?

@nokia2003
Thank you very much.. Now my baby is back.. But all my app and JB gone..
My software version is 3.13.. OK..?
How do I JB my phone.?
I will PM you on why I have to reset my phone and probably u could help me on that too.. Its all about Digi internet...

Hello, please refer to the FAQ page for your queries C=

For your Q3, you should need to enter the SSID only once and thereafter when you are at home your phone should be able to detect and auto-connect to it.

After reset my phone, I noticed my phone firmware is on 3.1.3 and I believe I cant JB. Do I need to dload 3.1.2 and restore it in itunes.. Pls advice..

@bluehypo
No, I did not save anything..

hi guys...

my iphone left speaker is slower than right speaker..
is diz normal? or i need to send for warrant?

i juz bought last week

If you did not, then I believe you will not be able to downgrade/restore to any firmware other than the latest (which for now is 3.1.3).