Time in PM or "Dating Calendar"

We all are in different TimeZones.
I't so often one inviting another for a date BUT, the calculating a time is boring and calculating is a source of mistakes.
So there are 2 ways to solve the problem:
1) make BBcode [time]dd-mm-yyyy HH:MM[/time] which will be automaticly calculated from sender's and recipient's local time when shown to recipient.
2) Dating Calendar: tool which makes everyone available to choose date and time for dating and invite someone for a date/chat. This tool also will show time in local time for each user.