Being a newbie in the iphone world, it was quite awkward at first trying to figure this and that (maybe I'm dumb or over-excited?) but I finally managed to customize it to my own liking.

New to iPhone? Guide here or just read the manual.

Why Jailbreak? here, here, here, here and more which you can just google.

Jailbreak and Unlock for 3.1.2 ? Blackra1n RC3

Install Cracked Apps on iPhone for 3.1.2? here

Custom Ringtones? Get iRinger

Telco logo and how to enable the Cellular Data Network menu in Settings (for malaysian) here

Walla and have fun.