The easiest and cheapest way to protect your work while writing it is to send yourself a copy via registered mail. This applies in Canada. For outside of Canada, please refer to the Copyright office in your city. It is wise to do this every time there is a significant change to the draft. Here, you are protecting the concept of the material, not necessarily the words, as the words may change continuously throughout the process. Although it is not required to do this several times, it is up to you to decide how significant a change one draft is from the previous, and what you want to have protected.
Make yourself two copies of the latest version of your work with the date in the footnote. The following should be included in an envelope: One copy of the document to be registered; and a signed letter from a witness stating that this is indeed your work. The letter can read something like “I, (witness’ name) have seen the enclosed document, and confirm that it is the original work of (writer’s name).” Sign and date the letter and enclose with the written document. Address the envelope to yourself, as well as include the return address. On the back, in small print, you can write in point form what’s enclosed and the date on the document. This is so that you don’t have to open it to know which version is inside.
Finally, when you receive the registered package, attach the second copy to it with a rubber band or in yet another envelope. Do not separate these. If ever there were a dispute in court as to the rightful owner of the document, you want to make sure that what’s on the outside of the envelope is identical to what’s inside before you break the seal.
If you are ever in doubt about protecting your work or copyright rules and regulations, refer to the Copyright office in your area, located in the government section of the phone book or online at http://www.ic.gc.ca/eic/site/cipointernet-internetopic.nsf/eng/h_wr00003.html