You need to download redsn0w to jailbreak your device.
It is okay to jailbreak your iPhone 3g. The only downside to jailbreaking your iPhone is that you will loose your Apple warranty.
Simply jailbreak your iPhone 3G or iPhone 3G and install Cycorder.
yes
PwnageTool 4.2
The iPhone 3G already have a camera that is capable of recording video. The inability to record video on the iPhone 3G by default is a software limitation rather than hardware limitation. To record video on an iPhone 3G, simply jailbreak your iPhone 3G and install Cycorder.
iPhone/iPod Touch/iPad iPhone: 1G, 2G, 3G, 3GS, 4 iPod Touch: 1G, 2G, 3G iPad
Multitasking does not work on a iPhone 3G, You must Jailbreak your Phone to do that (Beaware that your phone would be very slow with Multitasking)
Yes, use PDAnet to connect it. To get PDAnet you will have to jailbreak your iphone.
using redsn0w
This depends on the interpretation of the question. iPhone 3G has a camera that is capable of taking both video and still image, but Apple has limit the iPhone 3G camera to only taking still image. It is possible to take video on the iPhone 3G using Cycorder, but doing so require you to jailbreak your iPhone 3G.
Apparently it is fairly easy to unlock the iPhone 3G. By simply using a software application easily installed to do what is called a "jailbreak" on your iPhone which allows the download of unapproved third party apps and then following a few simple steps one can quickly have their iPhone unlocked.
you will have to jailbreak and unlock your iphone , there are lots of tutorials on this on websites. theres a tutorial on how to do this at : www.iphone-mod.com