Programmatically move items from one document library to another
The following code snippet explains the way to move items in one document library to another in a simple way.
I assume that, you got a SPListItem object.
SPListItem spItem = itemCollection;
SPFile srcFile = spWeb.GetFile(spItem.Url);
SPList destDocLib = spWeb.Lists[“MyDestDocLibName”];
srcFile.MoveTo(destDocLib+ “/” + srcFile.Name, true);
The above code will move the document (item) from source document library to the destination.