As an Autobot spy, Bumblebee is the ultimate robot in disguise. What he lacks in size and strength, he makes up for the courage. he enjoys the company of humans and would do anything for his Earthly friends.
Jazz (Modified Pontiac Solstice)
Jazz picked his sport car form because it's the epitome of style. If there's one thing he digs about Earth, it's human culture.
Ironhide (Modified GMC Topkick 6500)
Ironhide is the toughest Autobots around. More than one Decepticon has busted an O-ring just from seeing his narrow eyes. He sees himself as the cold, steel fist backing up Prime's inspiring words.
Megatron is the leader of the Decepticons. He will stop at nothing to establish his empire and destroy the Autobots, starting with Optimus Prime.
Starscream (Lockheed Martin F-22 Raptor)
Starscream has delusions of grandeur. He chose to resemble an F-22 jet because it's the pinnacle of human technical achievement. He serves Megatron but longs to fill his shoes.
Blackout (Sikorsky MH53 Pave Low III)
Blackout lives for the chaos of the battlefield and delights in destruction. As a military helicopter, Blackout also the heavy lifter that other Decepticons rely on for transport over long distaces.
Frenzy is a choatic spy turned boom box, sent by Decepticon to infiltrate enemy strongolds.
source : transformersmovie.com