What's the best way to get the offset from UTC to say EST?

Right now it's EDT, and the problem is that it has changed from -5.00 to -4.00 which is wreaking havoc.

As a result, I did a little playing and use Jan/1/1900 with a time value so that I get a consistant value. However, I'm pretty sure that this is going to freak out and die in other languages.

What I need is the exact same offset regardless Daylight savings or Standard time. (i.e. I always want the offset from Standard time)

Am I missing something because every function I can find always gets what it is currently unless I pass a date that is fixed, which only works for gregorian calendars and only for the northern hemisphere. (It should be backwards to us in the southern hemisphere for when they have Daylight savings time should it not?)

Thanks for the help!