There are source code examples on the internet that can easily calculate dates and times for different locations and they take into consideration Daylight Savings Time in those locations... here is one such example in VB:
http://vbnet.mvps.org/index.html?code/locale/gettimezonebias.htm
This code example along with others (on the same site) show that it isn't that difficult to accomplish what we've been discussing here. I also don't think that it's that difficult for someone to enter a few pieces of relevant time information. I didn't understand the analogy about software deadlines and software writers unless you were trying to imply that if someone that writes software can screw up a date then there is no hope for someone to get it right if they don't write software... Software writers are not exempt from screw ups... thats why there are bugs...
This has been "fun"... You are probably right... a suggestion like this probably isn't going to find itself in the codebase of MsgPlus... it's not as exciting as changing the color of the font for a contact or being able to configure Personalized Status... I would find it useful only because many people in my contact list are in different parts of the world... maybe I'll just write a plugin for myself... it might be a fun excersize...