Your State of Jailbreak:
Good news! There is a jailbreak available for your iPhone.
redsn0w, while a bit more complicated to use than something like limera1n or greenpois0n still is about as robust and full featured of a jailbreaking program that you can get. Using redsn0w 0.9.6rc8 you can enable Homescreen Wallpapers as well as Native Multitasking along with custom boot and recovery logos.