In SQL Server 2005 onwards, you can create database-wide DDL triggers, which fire when schema modifications are made. You could then use database mail to send email.
Please see: Using DDL Triggers in SQL Server 2005 to Capture Schema Changes
Here's an example which uses EVENTDATA() and logs to a table:
USE AdventureWorks
GO
CREATE TABLE [dbo].[tblMonitorChange]
(
[EventType] [varchar](100) NULL,
[SchemaName] [varchar](100) NULL,
[ObjectName] [varchar](100) NULL,
[ObjectType] [varchar](100) NULL,
[EventDate] [datetime] NULL,
[SystemUser] [varchar](100) NULL,
[CurrentUser] [varchar](100) NULL,
[OriginalUser] [varchar](100) NULL
)
USE AdventureWorks
GO
CREATE TRIGGER trgMonitorChange
ON DATABASE
FOR DDL_DATABASE_LEVEL_EVENTS
AS
set nocount on
declare @EventType varchar(100)
declare @SchemaName varchar(100)
declare @ObjectName varchar(100)
declare @ObjectType varchar(100)
SELECT
@EventType = EVENTDATA().value('(/EVENT_INSTANCE/EventType)[1]','nvarchar(max)')
,@SchemaName = EVENTDATA().value('(/EVENT_INSTANCE/SchemaName)[1]','nvarchar(max)')
,@ObjectName = EVENTDATA().value('(/EVENT_INSTANCE/ObjectName)[1]','nvarchar(max)')
,@ObjectType = EVENTDATA().value('(/EVENT_INSTANCE/ObjectType)[1]','nvarchar(max)')
-- Is the default schema used
if @SchemaName = ' ' select @SchemaName = default_schema_name from sys.sysusers u join sys.database_principals p
on u.uid = p.principal_id where u.name = CURRENT_USER
insert into tblMonitorChange
select @EventType, @SchemaName, @ObjectName, @ObjectType, getdate(), SUSER_SNAME(), CURRENT_USER, ORIGINAL_LOGIN()
From here.