You can easily find out an address if you find out if he's on tour. If he is, look at what venues he'll be playing at. Open up the Venues that DO/DO NOT pass on fan mail thread and compare. If none of the venues are on there, you can email them to see if they'll pass on your letter.

Hey guys!

Could somebody try and find me a via venue address so I can write to Bon Jovi and get my Have a nice Day tour Ticket signed that'd be great. Cheers {thumb2}