I have a CSV lists of nodes and edges, and load both accordingly in Gephi.
My node list looks like this:
Id Date weight
56079348 12.07.2009 141
77150491 25.09.2009 2161
612473 08.01.2007 94
621523 10.01.2007 128
I want to make node circles sized according weight column.
Is it possible, and if yes how to?
Yes it is possible, this is what the ranking panel is for.
Be sure to have imported your "weight" values as numerical values (Float, Integer, Long...), not textual (String). This can be checked in the import wizzard, at the step when you are asked to confirm / choose the type of each attribute.
Once you have made this check, visit the "ranking" panel in Gephi and select your weight attribute in the drop down menu. Then click on "Apply".
This tutorial has some slides on ranking, and more: http://www.slideshare.net/gephi/gephi-quick-start.