I doubt you would be able to find out about every moment of a symphony unless you got the complete score and studied it like conductors do. This could take many weeks or months of study,
However many books have been written about the major symphonies where the structure and general mood of each movement will be discussed and explained.
I searched the web for "classics explained" and found this as an example. A double CD with spoken word describing Beethoven's symphony number 6.
http://www.naxos.com/...item_code=8.558034-35
Also here is a section of a video that Leonard Bernstein made about Beethoven's 5th symphony (I remember watching it on TV years ago). You may be able to find other similar videos.
http://www.awesomesto...ains-beethoven-part-1
Here is a web site I found totally dedicated to Beethoven's 3rd symphony.
http://www.beethovenseroica.com/eroica2.html
I am sure you can find other web sites where other symphonies are explained.
I only used Beethoven above as examples, I am sure other composers will also have similar web sites.