Along with many others i have been frustrated at how Outlook does not have the ability to deal with scheduling appointments in a different timezone. This is important if you are a global worker and trying to schedule a meeting for 10pm in say Korea and you are in the US or New Zealand for example.
A couple of people have talked about this, notably Rod: Time Zone hell. I posted about this also: http://blogs.msdn.com/cjohnson/archive/2006/03/01/540805.aspx
After looking into this I sent the product manager for this functionality in Outlook and wrote an email about how frustrating it is for people today ... and how great it would be if we could do something about.
Well ... it looks like a solution has been included in Beta 2 of Microsoft Office Outlook 2007!!!
The screenshot below shows an appointment screen with two elements outlined in Red. The 'Time Zones' button that shows and hides the second element. The second is the two drop downs to let you pick a timezone for the start and an end time of an appointment. It is important to have both as for things like flights you might take off in one timezone and land in another.