[R] re-arranging rows in data frame

[Srinivas Iyyer]

Hi:
sorry for asking simple question (not simple for me though).

I have a data frame something like this:

ExpName Identifier value 
MM1-x1 GSK 0.02 
MM1-x1 GSK2 0.001 
MM1-x1 GSK3 0.04 
MM1-x1 GSK4 0.1 
MM1-X2 GSK 0.4 
MM1-X2 GSK2 0.1 
MM1-X2 GSK4 0.002 
MMX-X3 GSK 0.4 
MMX-X3 GSK2 0.23 



I am interested in getting a long table something like this:

 GSK GSK2 GSK3 GSK4 GSK..(n) 
MM1-x1 0.02 0.001 0.04 0.1  
MM1-X2 0.4 0.1  0.002  
MM1-X3 0.4 0.23    
MM1-Xn      


I am re-arranging my fields into more clean data frame. 

How is it possible to do this?

thanks
Srini