Simon, I hope you don't mind my jumping in here but I'm curious about this too...
The problem is this: his user says she wants a reminder e-mailed to her at 3:00 pm. She's currently in EST, so that's the timezone she chooses, and the system can calculate the time to send it to her with "GMT - 5".
The problem comes in when the user goes on Daylight Savings Time; the calculation has to be "GMT - 4" instead (for my example). His code needs some way of knowing which offset to use at a particular moment in time.
I'm sure there are rules about when DST starts and stops, but we were hoping there would be something already written to handle this.
