A few minutes ago, I submitted my first piece of software to Freshmeat (it hasn’t been approved yet; it will probably take a few hours): DailyTasks. It’s a small utility, written in PHP, with both a command line mode and a web interface, which, surprisingly enough, reminds you of daily tasks. 
The web page linked above tells the “story” in more detail, but, basically, I’m much too chaotic to use traditional task management programs (every time I tried, I seemed to spend more time updating tasks than actually doing them), but I wanted something to remind me, every day, of doing something — from “clean up GMail’s spam folder” through “update a blog” to “do the laundry, if necessary”. There was already a similar program (frequent-task-reminder), but it lacked some features that I wanted (such as non-accumulating tasks), and so I wrote my own.
It’s really basic stuff, with no bells and whistles, and the PHP code would probably scare you, so impressionable young people should avoid looking at it. But maybe — just maybe — you’ll find it useful.
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Why not Google Calender? It has SMS to Portugal for Free and a lot of things.
Marco: I haven’t tried Google Calendar yet, but I think a full “calendar” is overkill for what I want here: a place where I can go and see which daily, repeating tasks I haven’t done yet today, and mark them as “done” as I complete them.
Besides, this works offline, too.