The latest jailbreaking tool right now is "limera1n" and yun na daw ang last iteration kahit sa susunod na version pa ng iOS 4++..
all you have to do is download it then restore your device to the current firmware then use limera1n to jailbreak it, next next lang yun at your good to go.. ang sign na successful ang jailbreaking mo is kapag nakita mo na sa springboard ng device mo ang "cydia".
about apps naman eh meron tayong dalawang paraan dyan.. one is to download free apps from the appstore.. buy paid apps or installing cracked applications via "installous".. you can install "installous" in cydia pero kailangan mo muna mag add ng source sa cydia ("
www.hackulo.us") and install a patch "appsync 4.++" (depende sa kung anong version ng firmare mo).
after installing all of it restart your device (and pray na wag syang mag stuck sa apple logo) then you can now download and install cracked applications in "installous"
enjoy! heheheh