There are 49 Trophies that can be collected.

Bronze

Newbie coming!
Win your first nail'd event

Just started
Race for more than one hour

Greece Cup medalist
Win at least a Bronze Medal in Greece Amateur Cup in Tournament mode

Andes Cup medalist
Win at least a Bronze Medal in the Andes Amateur Cup in Tournament mode

Yosemite Cup medalist
Win at least a Bronze Medal in the Yosemite Amateur Cup in Tournement mode

Arizona Cup medalist
Win at least a Bronze Medal in the Arizona Amateur Cup in Tournament mode

Stunt Mania competition medalist
Win at least a Bronze Medal in the Stunt Cup in Tournament mode

Afterburner competition medalist
Win at least a Bronze Medal in the Burner Cup in Tournament mode

Pro World Cup medalist
Unlock The Grand Finale in Tournament mode

Glider
Fly more than 10 kilometers / 6.2 miles

Boost expert
Earn at least 200 boost feats

Boost master
Earn all possible types of boost feats

Crush master
Smash at least 100 opponents in multiplayer races

Airborne
Gain a boost feat using air control

Pressing hard
Gain a boost feat using pressure control

Unwelcome guest
Play and win 30 online events you have not created

Home sweet home
Play and win 20 online events you have created

Flying monster
Perform 20 Monster MTX boost feats

Flawless driver
Perform 20 nail'd Expert boost feats

Globetrotter
Drive a total of 1,000 km / 621 mi

Judgement Day
Gain a Terminator boost feat 50 times

Brave, brave Sir Robin
Find a shortcut that leads to a three headed knight statue

Wrecked God
Win a tournament race in which you crashed at least 5 times

Working on it, guys
Beat developer bests on 4 tracks

Got you, guys
Beat developer bests on 8 tracks

Faster than you, guys
Beat developer bests on all tracks

Stuntman
Fly more than 260 meters / 853 feet in a single jump

Still alive!
Wreck your vehicle 250 times

Dominator
Win race by more than 5.0 sec.

Heart of a champion
Win an online race with 5 other, higher classified players

Bronze collector
Win at least a Bronze medal in each of 49 Tournament events

Native of Greece
Win races on all Greece tracks in all modes

Native of the Andes
Win races on all Andes tracks in all modes

Native of Yosemite
Win races on all Yosemite tracks in all modes

Native of Arizona
Win races on all Arizona tracks in all modes

Quick like a bunny
Perform 5 boost feats in less than 10sec.

Never lose faith
Win an online race in which you were last after the first half of the track

The great battle of our time

Win an online race in which you smashed two opponents and were smashed twice 

Silver

Amateur World Cup medalist
Win at least a Bronze Medal in all the Amateur World Cups in Tournament mode

Competitor
Win 10 events in a row

Beat Jasiu
Beat Jasiu's time of 2:37 on Aqueducts in simple race with no mutators

Dangerous maniac!
Be at least 3rd in 100 online events

Not a scratch!
Win 5 online events in a row without crashing

And who's the best?
Win races on all tracks in all modes

Runner up

Win at least a Silver medal in each of 49 Tournament events 

Gold

Dirt devil
Win at least a Bronze Medal in the Tournament

A true winner
Win 100 online races

Golden guy
Win all 49 Tournament gold medals

Platinum

Got it all!
Unlock all other 48 trophies

http://www.ps3trophies.org/game/naild/trophies/