How to Download Apps To iPhone 3g (4.2.1)?

Okay i have a iPhone 3g and of course apps like facebook and such need 4.3 to download, how can i if i only have 4.2.1? Any ways? I can jailbreak phone if needed.

There may be an update if you look in itunes.

Of course, though, the only way to get those apps is a jailbreak. There are plenty on youtube for you! Here is one, not sure if it works, but jailbreaks are kinda risky.

Just an example. Hope I helped.

Not even jailbreaking would help in this case. You would need to get an iPhone 3GS at least (supports 6.0).