Looking for a simple reminder program that will span computers

I’ve run a program called Xreminder Pro as a desktop reminder program forever and a day.  It’s a very simple program with highly flexible scheduling and recurrence patterns.  When the reminder comes due, it pops up a window, makes a configurable noise, etc.  If you don’t hit the Accept button, it stays there, and will pop up again when you next start up the machine.  You can also click Snooze.

It really does everything I want in a reminder program — bearing in mind my expectations may be shaped by my having used this program since the mid-late-90s.

Whereby hangs the tale, because this is a one-person, one-machine, one-keyboard program.

What I would love would be for the database  for the program to reside on Net.  And to be able to run the program from multiple machines (at work, at home, my PC, Margie’s PC, etc.).  And be able to add to the reminder list from anywhere, and have it remind me anywhere.  So if I’m at work and want to remember something I have to do tonight, I can do that.  And I want it to pop up on Margie’s machine, too, so we both get harassed.

But have the actual reminder bits be exactly the same as it is now.

Alas, the program hasn’t been updated since the turn of the millennium.  And isn’t likely to be.  The last time I inquired about a new feature, I was pointed to a much more sophisticated and expensive program they were selling. Which is networkable in terms of being able to run it client-server on a Windows network.

No joy.

Now, there are plenty of online reminder programs out there, but mostly they remind you by (a) sending an email, or (b) sending an SMS message to your phone. Neither is a suitable for me (my emailbox runneth over as it is, and scrambling for my phone and unlocking it to spot a reminder is way too much effort).

I toyed with the idea of running xReminder with the data file sitting in, say, my Dropbox.  Unfortunately, the program reads its data file only from its home directory.  No way to configure it otherwise.  Ugh.

I may be able to use Remember the Milk for this — that tool has eleventy zillion ways of reminding, in particular sending a message through Google Chat (and to as many IDs as one would want).  It can also integrate with sidebars in GMail and Google Calendar,  send SMS, send Tweets, etc and so forth.  It will also (when working right) integrate with Google Calendar as an extra calendar … which gives it all the notifications available through that, including just what I want – popups.

The main drawback here is that there’s no easy snooze button on a reminder.  It’s too easy click it, shut it, and forget it.  Believe me, I know.

For quite some time we ran a copy of this on just my machine. Then I broke down and bought another seat for Margie, and we put all our birthday reminders on it.  Unfortunately, we’ve never moved it over to her new PC, which is why now we keep missing people’s birthdays.  Meanwhile, I’m at the point where I need to move it to my new work PC, but I really want it networkable so that I can set a reminder to do something at home.

So, does anyone have any brilliant solutions to this?  I don’t want or need an elaborate to-do system.  I just need:

1. Ability to quickly enter in a task / reminder.
2. Enter in a simple time or a recurrence.
3. Keep It Simple, Stupid.
4. Can be entered from multiple locations.
5. Reminders pop up on any of several PCs.
6. Reminders pop up in a way that can’t be missed.
7. Reminders can be snoozed, but are not actually closed until accepted — even if the machine is shut down.

Anybody got any brilliant ideas I’m not thinking of here — either an answer to what I’m looking for or some alternative approach I’m not thinking of?