VS 2010 Add data to an excel document

Is it possible to do the following.

I want to make my program to add data to an existing excel document.
In the program I will have a few textboxes, and one button to add the info, it must be added after the following day info.
In my excel I have dropdown list that if the correct info for certain columns is not match it gives me an error to say that the info is wrong.

Is there a sample to do this.