My "secret" way:
1) get a small electronic scale (usu around $10)
2) walk into any resto that presumably has truffles
3) ignore any "truffle" item in the menu
4) ask the waiter to bring the real thing for you to smell
5) if you like what you smell, ask him how much per oz. A "reasonable" price goes (as of now) from $130 all the way up to $300 per oz, it's more expensive for bigger & nicer pieces.
6) 1 oz truffle should be enough for 3 people. Weight the piece you're going to buy.
7) Ask for a plain polenta or pasta dish (some people do it on eggs, I don't)
8) Ask for the truffle to be shaved at the table, or just do it yourself.
9) Wash down with something appropiate for the occasion, like a nice Barolo.
10) Enjoy, you should be in Heaven at this point!
At The Peninsula BH, the Belevedere restaurant had a guest chef who served a truffle tasting menu. I believe he is there a few times a year. I forget his name, though. He also just did an end of summer dinner. He used to be head chef at L'Orangerie. If he does the truffle dinner again, you should go. His name is Alain something I think.