How to obtain the current time differences between two timezones

Question

I want to calculate the current time differences between US/Central timezone and British Summer Time. I mean, currently these both timezones have daylight savings going on, so they have a 6 hours time difference. But after Sunday October 31 2010, daylight savings will be off for British summer time, at which moment there will be a 5 hours time differences between these two timezones.

Is there any way I can calculate these varying time differences?

Answer 1

Just to provide some concrete code for the answers given, here's some code to work out the current difference between me (in London) and my colleagues in Mountain View:

using System;

class Test
{
    static void Main()
    {
        var london = TimeZoneInfo.FindSystemTimeZoneById
            ("GMT Standard Time");
        var googleplex = TimeZoneInfo.FindSystemTimeZoneById
            ("Pacific Standard Time");

        var now = DateTimeOffset.UtcNow;
        TimeSpan londonOffset = london.GetUtcOffset(now);
        TimeSpan googleplexOffset = googleplex.GetUtcOffset(now);
        TimeSpan difference = londonOffset - googleplexOffset;        
        Console.WriteLine(difference);
    }
}