Help with jailbreaking and Cydia for iPhones, iPads, and iPod touches.

Not sure why iphoneblogrcom got suspended but he's right. Redsn0w injects the jailbreak and cydia, while pwnagetool creates a custom ipsw file with the jailbreak and cydia integrated into it. But the end result is nearly the same. And as he says, the advantage of pwnagetool is that you can preserve your baseband. However, if you have an iPhone4 you can also preserve your baseband using Tiny Umbrella and you can use Redsn0w to jailbreak afterwards. One thing I am unsure about is that I know that redsn0w allows for animated bootlogos. I am not so sure about pwnagetool.

No, they do the exact same thing just in different ways. Redsn0w installs Cydia onto your current firmware and Pwnage Tool creates a custom firmware with Cydia bundled. The only reason you would want to use Pwange Tool over Redsn0w would be if you wanted to preserve your baseband to unlock.

There is to my knowledge no real difference apart from the method used to jailbreak

I always found PwnageTool jailbreaks to be more stable. Don't have any hard evidence, but I've been with the JB scene since the beginning and have enough experience to make that claim.