I am mailing out reminders to potential customers and the time is getting converted to our servers timezone EST (I think it is currently using EDT though as appropriate). I need to store the timezone for the potential customer and translate the time into their current timezone.

I can store the offset but I am worried about daylight savings time. I can always store a non-DST offset but that causes issues when the signup appointment is scheduled before DST but occurs after DST.

Ideally I would like to store a timezone and have salesforce translate the datetime to that timezone accounting for DST if necessary. How can I do this?