properties.AfterProperties["Internal Name of the column"]ž

you should go through this article:

Working with BeforeProperties and AfterProperties on SPItemEventReceiver - Blog http://www.synergyonline.com/Blog/Lists/Posts/Post.aspx?ID=122

It will help you better understand what is going on in Event Receivers.

properties.AfterProperties["Internal Name of the column"];

you should go through this article:

Working with BeforeProperties and AfterProperties on SPItemEventReceiver - Blog http://www.synergyonline.com/Blog/Lists/Posts/Post.aspx?ID=122

It will help you better understand what is going on in Event Receivers.