Discussing work in progress I am about to begin my hunt for post-doc positions. As such, I will be discussing my dissertation work in some detail with potential post-doc advisers.

I am currently in the data collection phase, and none of this research has been published. I am somewhat worried because, as a requirement for my PhD, I have to contribute novel research to the field. I hope to submit a part of my dissertation to a conference; however most relevant conferences are not until next summer, and submissions are typically due early next year. In other words, this research will not be published for a while.

Is it appropriate to ask for some discretion when discussing my dissertation with professors who do similar research?
I think the following won't apply to you, but may be useful for people in other fields with the same question.  

If you work in a field where putting preprints online is an accepted practice, then write up your work and upload a preprint.  In this way you clearly establish priority without needing to wait for the article to be refereed.

For instance, in Physics, CS, and Math, most researchers put preprints on arXiv.org.