Spam in Sending email using Send Announcement Module v0.2

[Thana]

Hi
In our site we have nearly 6000 users, wanted to send announcement to users,
as the user number is large it will send email as spam, Is there any way we can limit the number of emails to go in an hour, so that all the emails will be send with out spam.

[tarok]

how can you even send an email to all members at once :$?