No other smartphone forum is as busy as CrackBerry, ask a question on another forum and see how long it takes you to get an answer. There is over a Million members here, the forums stay moving..
I agree, The iPhone blog is a pretty responsive site. The forum mods are usually big participants in the help over there, just like here. Questions are usually answered rather quickly over there from what I have seen.
try modmyi.com (sorry, can't post a direct link to the forum yet).
great place to get themes, wallpapers, ringtones, news - but i've mainly used it to, uh, help me figure out how to use the phone on a carrier besides at&t!