I've noticed over the years getting iphone info is all over the net, but to get detailed specifics on all its features are far and wide. The use of the Apple website is great, but sometimes the info is buried behind quite a few pages of ad like propaganda and/or trying to sell you the item info instead of its user guides. so here is the exact location of the most helpfully iphone parts of apples website.
http://support.apple.com/manuals/iphone/
http://www.apple.com/support/iphone/