May I ask what program you are using to write this book?
Do you also have an ereader to test on (Nook, Kindle, Kobo, etc.)?
No, stay far away from Calibre for anything you want to be released professionally.
It is an ok tool if you want to use it for personal conversion. It creates bloated code, and depending on what the original->converted file type is, errors may be introduced.
Some people use a one stop shop to spread your ebook to many different stores, such as Smashwords or Lulu. The downfall of this is that they take more of a cut than handling the stores by yourself.
https://www.smashwords.com/about/how_to_publish_on_smashwords
http://www.lulu.com/publish/ebooks/
If you have any questions on Self-Publishing, there is also a ton of questions answered on MobileRead. Here is their “Author’s Forum” where lots of questions/answers can be found about self-publishing:
http://www.mobileread.com/forums/forumdisplay.php?f=75
Here is a Stephan Kinsella article I found on the topic:
http://c4sif.org/2012/02/are-creative-commons-licenses-even-enforceable/
Release it under CC-BY, and spread it far and wide.
People will pirate the stuff whether you like it or not, so put it for free on your website for all to read, and also have it available for purchase at the big retailers (for a cheap price, like $.99-$1.99):
Amazon and B&N are the big two you definitely want your books sold.
iBooks is the third largest, but it is a COMPLETE PAIN to get your stuff on there. It would be easier to go through something like Smashwords for that.
Beyond that point, the rest of the stores only hold a very small market share, although some niche ones might be better depending on the genre.
If you need any help converting things to EPUB, I would be glad to help with that. You can take a look at all of the EPUBs I converted here (some are already accepted on Mises):