We do it without storing a user's time zone via jQuery and a custom script that converts all UTC time stamps on a page to the local time setting of their comput

We do it without storing a user's time zone via jQuery and a custom script that converts all UTC time stamps on a page to the local time setting of their computer. This works well for us because we have travelers who use the service through a variety of time zones. The second touch point is our iPhone app, and the SDK has built-in support for converting UTC to the client time.