Both examples in the question are legitimate ways to say a plan will be published sometime before the end of this year. A number of ways of saying about the same thing are listed below. The list contains forms from the question and from previous answers, besides some forms I added.
- The plan will be published in 2013
- The plan will be published this year
- The plan will be published 4th quarter
- The plan will be published within the year
- The plan will be published before year end
- The plan will be published within this year
- The plan will be published before the year ends
- The plan will be published by the end of the year
- The plan will be published before the year is out
- The plan will be published by the end of this year
- The plan will be published by the end of this calendar year
Forms 1, 2, 5, and 9 are direct, accurate, not ambiguous; I recommend using a form like 1 or 2.
Form 3 is a bit jargony, and also pins the publication date to a specific quarter of the year. If that is accurate, you can use form 3; or might revise it to (eg) “The plan will be published 3rd or 4th quarter”.
I regard form 4 as direct, accurate, and a not-ambiguous reference to the current year. By contrast, a previous answer claims it refers to the 12 months ahead instead of to the calendar year.
Form 6, with its “within this year” phrase, strikes me as clumsy and unnatural. Form 7 is not as good as form 5; I'd recommend against form 7.
The “published by” phrase in forms 8, 10, and 11 is bothersome. It is a little like saying the end of the year is going to publish something.