I´ll start and expand the list in the next days, any corrections and ideas are appreciated. If there is already some summary please let me know... Thank you!
So what I found:

Example:
I´m author (songwriter, composer, ...) which finishes the work (track, lyrics,... ) and before
using, broadcasting , etc. the work somewhere I´d like to have guarantee (at least good feeling about that :- ) to be the owner of the copyright.
1) Automatically when I write or compose something it is copyrighted.
2) Local company which provides services for songwriters, composers, musicians, ....
3) I, you join ....
* ASCAP (The American Society of Composers, Authors and Publishers; founded and run by composers, authors and publishers which makes up it's membership) or ....
* BMI (Broadcast Music, Inc.; run by broadcasters) or .....
* SESAC (Society of European Stage Authors & Composers) - not easy to be a member
* The Guild of International Songwriters & Composers (UK) - http://www.songwriters-guild.co.uk/home.htm
* PRS - Performing Right Society (UK)
4) I, you: can register my work on http://www.copyright.gov/ (under http://www.loc.gov) - very slow process (by mail), online system is faster
5) .....
(The "envelope" system - time stamp)
ASCAP explanation http://www.ascap.com/musicbiz/copyright_tips.html
thanks for your opinions and experience
Vašek