This program, which has laid dormant on my computer for years, is my new obsession. Great for us crazy planners with the flexibility of making changes instantly.
I'm still a fan of the Moleskine planner (aka good old pen and paper) especially as a memento that you can look back on and see how your days have been spent, but for tentative plans that could change any moment (and I have a fair share of those) use the iCal.
But what do you think?