Hi
I am the developer of MailShot Pro, thanks for the mention.
I just thought I would add that, although there isnt a version for OSX, you can use the special contacts that MailShot creates for your groups in Mail on your mac too.
Heres a link to a how-to How can I send mail to a MailShot group from a Mac ?
I'll also repeat the tip that people find most useful:
For best results address your emails to MailShot groups by tapping on the blue “+” button in the “To:” “Cc:” or “Bcc:” line of Mail (or thousands of other apps) and select the group from your address book. (If you can’t find the contact that MailShot created at first, tap “Groups” and select “All Contacts” first.)
Any questions, just drop a line to mailshot@solubleapps.com
Cheers
Peter
Soluble Apps
Disclosure: I am the developer of MailShot Pro, and may benefit from it's sale.