There are 12 Trophies that can be collected.

Bronze

Lightning Reactions…
Win 'Fastest Finger First' Round in under 4 seconds (single player game)

Breaking the Ice
Answer the first question correctly (single player game)

That's what they are there for
Use a lifeline (single player game)

Fall at the first post…
Get the first question wrong (single player game)

It's easy when you know…
'Walk Away' with nothing (single player game)

Not going home empty handed!
Reach 1000 (single player game)

You're a brave contestant!
Choose to 'Walk Away' between 32,000 and 250,000 (single player game)

Silver

So Close!
Choose to 'Walk Away' with 500,000 (single player game)

…and yet so far!
Fail to answer the Million – dropping to 32,000 (single player game)

The million dollar question!
Get to the Million Question – Tier 15 (single player game)

You're a Millionaire!!
Win 1,000,000 (single player game)

Gold

All too EASY!!
Win 1,000,000 with all three lifelines remaining (single player game)

http://www.ps3trophies.org/game/who-wants-to-be-a-millionaire/trophies/