You can simply do it by doing:

> Gets a value that specifies the content type of the list item.
> 
> Returns a ContentType.instance representing the content type of the
> list item.

    SPContentType = properties.ListItem.ContentType;

so for item **adding** it will be:

    public override void ItemAdding(SPItemEventProperties properties)
    {
        SPContentType ct = properties.ListItem.ContentType;
    }

http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.client.listitem.contenttype.aspx

In the item **added** event its slightly different

    public override void ItemAdded(SPItemEventProperties properties)
    {
        
        SPList list = properties.listName;  
    
        string ctName = properties.AfterProperties["ContentType"].ToString();  
    
        SPContentType contentType = list.ContentTypes[ctName]; 
    
    }

hope it helps :)