Not sure what exactly you are looking for. And I'm not sure how detailed you want to get. However, I have been doing some research on various topics on software metrics. One of the topics that I am exploring is the Constructive Cost Model (COCOMO II). It uses SLOC to estimate the overall cost of the project (alternatively, it uses unadjusted function point counts).
<BLOCKQUOTE><font size="1" face="Verdana, Arial, Helvetica">quote:</font><HR>Originally posted by sophi: Which size estimation technique to be used and how to track the actual size? Can size be defined as Man-days??<HR></BLOCKQUOTE>
As you put the question, I assume you're refering to project size (not application size), which could be expressed in man-days.
Traking the actual size versus estimation is possible directly from MS Project, if you keep the project plan in MS Project.
About how to actually estimate it, it's a different question, which I don't think it could get a brief answer. Anyway, in my opinion, it should be based on your previous projects data. But, that's a project management issue, not QA.
... Not even me.
If you are looking at size estimation of a application for full SDLC then estimation by function point method is also one of them. You may refer to IFPUG site for more details on this. It also provides formulas for minimum number of test cases etc.