World Cup KickOff is all you will ever need for knowing all the match details for the upcoming World Cup 2006.
You can download and keep all the fixtures you are interested in so you will never miss a single game! Just download the calendar file specific to your calendar app and install it.
There are customized schedules for various calendar types (mobile phones, MS Outlook, et al). There are also RSS feeds available, although I haven't tried that.
You can even personalise the matches you want using the filters given. Either choose all teams, single groups or individual teams. You can also get the times for your local timezone.