Here are some tips that might help you:
How do you find out which venue/movie set/etc the person is performing at?
TicketMaster.com

The Internet Movie Database

Playbill.com

The Internet Movie Database
Don't forget to check bands/singer's official websites for tour dates.
How do you know when to send to VV?
If we're talking about a concert, you send it that it comes 3 days before. On the envelope write (usually on the front side so it's easier to see): Please hold on for artist name (date of performance).
If we're talking about a filming-you'll find the dates of filming at the same topic as an address.
How do you use The Internet Movie Database?
type actor's name and you can see if he is filming any movie at the moment. After you can use search engine on fanmail.biz which is at the top of the page. There you check if anyone before you requested an address of that movie. If not, you can request it at: viewforum.php?f=124


What about future movies/series?
You can request a VV address before they start filming but you should write there when they're filming ;)
What do I need to know about writing to a band/singer?
You can find all info about this here: Insiders guide to VV requests (click on the title)
How do I write down the address?
Movie sets:
Actor's Name
''Title of Movie''
c/o production company
Address
Concert arenas:
Band/ Singer's Name
c/o Arena
Address
Don't forget to check the list of Venues that do/don't pass on fanmail.
Good luck with your requests!

Urša