Here's the security setup that's required:

--create the role in msdb

USE [msdb]

GO

/****** Object:  DatabaseRole [CanSendEmail]    Script Date: 11/03/2005 09:31:08 ******/

CREATE ROLE [CanSendEmail] AUTHORIZATION [dbo]

grant select on sysmail_account to CanSendEmail

grant select on sysmail_profile to CanSendEmail

grant select on sysmail_profileaccount to CanSendEmail

grant execute on sysmail_add_principalprofile_sp to CanSendEmail

grant execute on sysmail_add_profileaccount_sp to CanSendEmail

grant execute on sysmail_add_account_sp to CanSendEmail

grant execute on sysmail_add_profile_sp to CanSendEmail

grant execute on sp_send_dbmail to CanSendEmail

--create the login

CREATE LOGIN [emailonlyuser] WITH <A href="mailtoASSWORD=N's@'">PASSWORD=N'somepassword', DEFAULT_DATABASE=[yourdatabase], DEFAULT_LANGUAGE=[us_english], CHECK_EXPIRATION=OFF, CHECK_POLICY=OFF

GO

use yourdatabase

GO

exec sp_adduser 'emailonlyuser'

Grant execute on prcSendmail to emailonlyuser

GO

Use MSDB

GO

exec sp_adduser 'emailonlyuser','emailonlyuser','CanSendEmail'

GO