SPItemEventReceiver - SPItem SPField updated

public override void ItemAdded(SPItemEventProperties properties)
{
// Check that ths is the list we care about
if (false == string.Equals(properties.ListTitle, "ListName", StringComparison.InvariantCultureIgnoreCase))
{
return;
}
// Check if this is the Field name that we care about
if (null == properties.AfterProperties["FieldName"])
{
return;
}

// If you get here, field was added/updated.

}