Also know as "Automatic follow up emails for new users".
I've attached a beta version of the new (2.0 branch) of the Automessage plugin.
Whilst the name and functionality remain the same, this plugin has been completely re-written to remove the need for any external tables (using custom post types now).
I've initially released this as a beta, rather than just post the update, due to it being completely new code, and also because this early version will *not* transfer across any currently set-up messages or queues from the old version of the plugin.
When we release this version as the full 2.0, it will have a transfer facility built in, but for now if you want to use it you will need to copy all of your existing messages somewhere safe, and then recreate them in the new version.
If the current version is working fine for you (and you have queued messages) then you can leave that running as you initially won't notice any new functionality in this version.
We've been running this version over on BuddyDress for the past 2 weeks without any issues so far.
Note: the menu location has changed for this version and will now be at the bottom of the WP main menu (left hand side).