Chicago had a pre-screening of Transformers at it's IMAX, an event attended by Seibertron.com. They have written a nice little summary of the new sceens, which you'll find below or originally here.
First off, there was no more than TWO MINUTES of extra footage,
dialouge, etc. NONE of the footage contained new CG. I will list the
new scenes in order of appearance.
1. Additional footage with Sam and Miles
- (Placed right before arriving at the party on the lake with Sam's
friend Miles) Sam arrives at Mile's house with his brand "new" ride.
Miles lives on a hill, it looks something like San Francisco. They
exchange a few words before jumping in and cutting to the next scene
(original scene of Miles and Sam driving up to the lake party)
2. Extended cop interrogation scene
- After the 50-cent line and Sam saying "Are you on drugs??" There is
about a minute more of dialouge between the cop, Sam's dad, and Sam.
There is another kid in the background with a mohawk being held for
some other charge. The officer tells Sam's dad he needs to see a video
to "get the message". It is the old "Don't do drugs" video of the girl
swinging the frying pan around the kitchen. Sam grumbles that he gets
the message and they are finally out of the police station. Here is a
link to the video they make him watch! It's classic, especially if you
are a Robot Chicken fan! http://www.youtube.com/watch?v=qyXFN4ocN_o
3. Extra bits in the Sector Seven Escalade after being taken from Sam's house
- After asking the kids about aliens, Simmons attaches some archaic
looking device with a tube and eye attachment over Sam's right eye
ball. A screen he is holding has a blown up view of Sam's eye. He is
using this device to determine how truthful Sam is being. He calls him
a liar again and detaches the device. Mikela then says her line about
him being a mall cop. Then Simmons gives the line of "Criminals are
hot..." but this dialouge is extended and he makes another comment
about how he would know from his line of work but not from personal
experience or something. Then the ticker goes crazy and Prime stops the
car.
4. Hoover Dam briefing - Before
Simmons talks about NBE's to everyone outside the dam, he has some
lines about Area 51. "You guys have heard of Area 51?" "yeah" "Well
this is Area 50!" then continue to NBE lines.
5. Pre AllSpark and "Energizer Bunny From Hell" extended scene
- The dialouge "You're about to see our crown jewel..." is extended and
the footage is completely different. They are outside of the office
where they view the AllSpark from. Simmons goes on some rant about how
all the presidents have been in this room since Hoover, and they are
going to get the opportunity that only presidents have gotten. He names
each president quickly and it is quite humorous. Calls our president
"W". Then they go into the room and the scene continues as normal.
6. Rhonda's Pawn Shop revealed
- This is the best of all the extra footage. Lennox is pleading with
the owner of a pawn shop to give him the short-wave radios Eps uses to
radio the Raptors. Lennox is doing a bad job and gets frustrated at
which the robust pawn shop owner pulls a gun on him. He flatters the
woman and she is charmed. She gives him the radios and the scene cuts
back to the regular scene of Lennox handing the radios to Epps.
7. Extended IMAX Credits - I guess this counts? There is a static scene of IMAX Credits at the end of all the other credits.
I'm not sure why, in the original report, the writer believes Starscream fired on Megatron at the end of the movie. We had been told the ending was changed, with Starscream originally flying off before Megatron was defeated.