Trying to go "professional" (music composer)

I am an utter novice and layman when it comes to matters of copyright law, production, etc., and naturally, the place to go to for such advice is the SDMB:

I’m an amateur music composer and have done a recording of my compositions. (They’re all relatively short compositions, a few minutes in length, piano pieces.) It took a few years to get this music album fully composed. I’m planning on publishing the music on Amazon, in a CD, etc.
But copyrighting and all that is where I get absolutely lost. I don’t know how to copyright the music, how to have my music available for download on sellers like Amazon, and how to get music CDs made “professionally” (however one defines that.)
Has anyone here at SDMB gone down this route before and can offer advice? Do I need to send my music to the Copyright Office with a form, a copy of my music, and some fee?
How do professional musicians usually get music CDs made? (The formal-looking ones with CD jacket/cover, disk case, disk labels, etc.) Through a company?
How do musicians sell their music MP3 recordings as downloads on websites like Amazon? Do they have to “apply” for Amazon seller privilege and get approved?
Is there any substantial difference between copyrighting music and literature such as a novel?
Is my music technically “steal-able” or plagiarize-able before I get it copyrighted? (In other words, one should get one’s music copyrighted ASAP?)

Any help would be greatly appreciated. I’m perplexed.

My understanding is that copyright exists as soon as you have created your music in some kind of tangible form, ie written chords, melody, etc or a recording of you playing it. It is illegal for anyone to plagiarise your work at that point. The difficulty is that you may need to prove you wrote the music first, that is where copyright offices can help.

http://en.m.wikipedia.org/wiki/Copyright#Obtaining_and_enforcing_copyright

I can’t help you more than that as I’ve never bothered to go down the route of officially copyrighting something.

Thanks! That’s helpful.

You will probably want to register your copyright. Go to copyright.gov and download the forms.

Thanks, will check it out.