The good news for Mac users is that OS X has, since version 10.4.5, included the new schedule; the recent software updates provided corrected settings for time zones outside the US and patches for 10.3 and Java. Better news: since OS X and similar Unix-like systems use Universal (Greenwich Mean) time internally, Mac clock chips don't have to worry about DST; the offset is handled in software. Windows, on the other hand, sets the hardware clock to local time; this causes the Boot Camp "five hours off" behavior and is the subject of much gnashing of teeth.
Of course, if it were a Mac-only world, things would be shiny and clean, but real life is gritty and messy. Assuming you're running some products from Microsoft, you can get the basics for fixes and updates here. Unfortunately, it doesn't seem that things are going all that well with the big MS and DST: reader Chris points us to where eWeek has the scoop on the frustrations. Better call and check those brunch plans.