When I compare my results to others in the literature should this go in results or discussion? In a Geopyhsics paper going into a more general interest journal (say PNAS as a good example), with the headings,


Introduction  
Materials and Methods  
Results  
Discussion  


I plan to have 3-4 paragraphs in which I compare my results with other results in the literature.

Should this section go in the results or discussion section of my paper? The comparisons are what will be of most interest to the majority of readers of the paper and my results are most relevant when viewed in the context of earlier results.
The results section is for your results. The discussion section is for discussing them - and this includes the significance in light of other results.

Keep the former purely for statements, the facts of the matter. The latter is where you move into interpretation (and expanding on very brief comments which are necessary for reading results reported).