At work i have to do some AMF3 delivered through php, so i finally have an excuse to have a look at ZendAMF.
First i follow the classic implementation which is pretty simple, you can found it here. It works well and i found no problem using it.
The main advantage i like in this approach is the possibility to have a progression info, cool.
The other cool thing is that rob offer us two articles, one with php sending AMF to flash and the other flash sending AMF to php.
Everything is very well explained and gave us example with custom data format aka class mapping.
There are some tips revealed that can save your day, like adding a newline in your php to have correct interpretation in flash or avoid URLVariables in flash, or how to get flash AMF from php with this :
// Get the contents from the stream
$amf = file_get_contents('php://input');
// Remove first byte (new line)
$amf = substr($amf, 1);
You can found the articles on the Rob[on]code blog here :