WordPress plugin for automated common Twitter activities
Based on Joey's Twitter-Auto-Pilot project.
For what this plugin can be good for check the README of that project or his super-detailed blogpost.
The difference here that it's a fully functioning WordPress plugin where you can set all the parameters in the admin area under "Settings >> Reading".
IMPORTANT: Since the process runs in a Cron job I stronly advise to turn off the default WP Cron and setup a normal Cron instead as described here: Properly Setting Up WordPress Cron Jobs. And it's not because it wouldn't have precise scheduling, but it's a very lengthy process that can take up to several minutes to run, and it would cause timeouts for normal website visitors.
The library for Twitter communication is from Abraham Williams, though I'm not exacly sure which version is this beside that it's small and works.