There is a new class as of .NET 3.5 named TimeZoneInfo that is much better than what we have right now in mojoPortal. For example once we implement this users will be able to select their time zone on the profile page, as they can now, but we will be able to automatically adjust for daylight savings time.
The only reason I have not yet changed to this yet is because last time I checked it was not supported in Mono and I don't want to break compatibility. It may be implemented now, I will check again soon. However I think there will be a downside to this in that the Time Zone names will no longer be easily localizable.