Need Recommendation for "Reminder" Software

I'm about to start writing reviews for a business. I want them to appear natural, but at the same time, I need them all up in about 4 weeks. I'm writing reviews to multiple sites so what I would like is some kind of software that would remind me to do a specific task at a specific day & time. Run one site on a 4-day schedule, another on a 7-day schedule, etc...

Someone once told me that Outlook did this, and I was going to use it, but now I've decided to keep this crappy Thunderbird, and so I need something other than Outlook.

Any help appreciated & thanks in advance.

if you have thunderbird open all the time you can use this add on...
https://addons.mozilla.org/en-US/thunderbird/addon/lightning/
it adds calender functionality to thunderbird. See if that helps

Microsoft Outlook could easily do this, I'm sure the Go0gle boys have something floating around also. check download dottie comie also