Michael Kobus asked how to send mail to undisclosed recipients.
Every email program has three fields for recipients:
To: The person (or people) the message is addressed to.
Cc: (carbon copy) Although the message isn't addressed to this person, you want them to see it, anyway.
Bcc: (blind carbon copy): The same as above, but you don't want other recipients to know that this person got the message.
If you want to send an email to a bunch of people, and you don't want to share that list with the people you send it to, put all their addresses in the Bcc field rather than To or Cc. It's as simple as that.
Well, not quite. There's still the question of what you put in the To field.
The first time you experiment with this, leave the To field blank. Depending on your mail client, the message may go out addressed to "undisclosed recipient" (the Bcc recipients will all receive it, of course). I know from personal experience that this works with Gmail.
Other programs may not let you send a message with an empty To field. In that case, you can just address it to yourself, so that people see a message from Michael Kobus, to Michael Kobus. If you really want it to go out addressed to "undisclosed recipient," you can add a contact to your address book with that name and your own email address.
One more thing: The recipients won't be the only people who can't see the addresses you entered as Bcc; after you send the message, you won't see them, either. So you may want to keep a separate record of the addresses you're sending the mail to.