Media streaming basics - HTTP vs RTMP

I am very new to media streaming, and I have some basic doubts to clear :

1. As far as I can understand, the difference between HTTP streaming (say through Apache) and a RTMP streaming (through Red5) is that streaming servers provide buffering and advance controls like seek, etc. Am I right ?

2. Can I stream only flash videos from RTMP servers like Red5 ? If I have to stream varying formats of files, do I have to go for HTTP streaming ? Can I use tools like xuggler to dynamically transcode files and send according to the request from the Red5 server ?

I am posing all these doubts because I have to provide streaming to all mobile clients - iPhone, Blackberry, Android - iPhone does not support flash, so is it a good idea to go for Red5 ?