[Systems] e-mail blast query

[Chris Leonard]

 Hi Sean and systems folks,

I've recovered the 2800-odd user e-mails from the old Pootle instance
(the user table was not migrated) and I want to send out an e-mail
blast inviting them to re-register and begin translating for SL again.
Currently the list in in spreadsheet format, but I can obviously
reconfigure as needed,  I've got fields like their previous user-name,
firtstname, lastname, e-mail address that I would like to use to
customize the messages.

I do NOT want to just recreate the user accounts on Pootle, at this
point, I'd prefer an affirmative action on their part to rejoin our
L10n community.  I don't really want to drop them into the L10n
mailman list and make them unsubscribe, that just seems obnoxious.

I don't want to get labeled as a spammer, but I'd like to send as
cjl at sugarlabs.org (if feasible).

I'm looking for suggestions on tools/services to do the mail-merge and
blast.  I see this as more-or-less a one-time effort to invite them to
come home to our L10n community.

TIA,

cjl