How does iron fitting differ from driver/fairway wood fitting?

Hi All, 

Earlier this year I went through the fitting process and replacement of my driver and fairway woods and now I need to replace my irons as my png irons are not conforming grooves and I play in tournaments quite a bit.  I am wanting to understand the main differences between how most fitters would differ between woods and irons in their fitting process?  

Thanks all, 

Blair