Dear Jack ,
As far salary package are concern.. more it depends on your capablities .. both the branches hving good future scope but if i wud have to choose btw these two then i wud hv opted for chemcial @ IIT guwahti even though the cut off in this is not as high as metallury in kharagpur .. acc to me it depends on your choice .. u need to simply have passion for what u are doing. so just clear ur mind and think of what u love best !!
All the very best for your future !
For more details please check out the links provided :
Click the link below link for opening and closing rank of IIT :
Cutoff in new IITs check the link give below :
http://jee.iitd.ac.in/openclose09.htm (this link includes the more detail analysis)
for code of the cources check the councelling broucher 2009.
Please feel free to post as many doubts on our disucssion forum as you can. If you find any question difficult to understand - post it here and we will get you the answer and detailed solution very quickly. We are all IITians and here to help you in your IIT JEE preparation.