The following offsets are for
Pokémon Emerald (U).
In the offset 080308AC you can replace "B1 08" with "91 10" to skip the whole intro except for the name selection.
Naturally, you're gonna be forced to use the male main character.
Otherwise, if you also want to skip the name selection, you can replace "B1 08" with "31 16" instead.
The ASM Routine that allows you to give the playable character a name is located at 08031090.
So using callasm 0x8031091 in a script will allow you to name him.
The problem with this is that setting the name plays the whole scene inside the truck.
The offsets of the different ASM Routines that as a whole composes the Professor's Intro are:
08031104: This one is executed after setting the character's name.
08031144: The game runs this one a lot of times after the previous one.
08031188: This one runs until you answer the Yes/No question about your character's name.
08031220: The game runs this one a lot of times after answering "Yes".
08031258: This one runs after the game stops executing the previous routine.
0803133C: This one runs while Birch talks to you after setting your name.
080313E4: This one makes the Professor dissappear.
080314C4: This one draws the main character's sprite.
08031580: This one handles the sprite while it fades and slowly becomes an Overworld sprite.
080316BC: This one runs after the previous one.
08031630: The last routine, it makes the game begin and sets the playable character in the beginning map, Inside the Truck.
These offsets were found by
Samu from Wahackforo
right here.
EDIT: Samu completed his research and here's the result.
To skip the introduction entirely, including that one small glimpse of it (
the 3 green bars from the background), you can write the bytes "31 16" in 08030440.
If you want to give a name to your playable character, there's a better ASM Routine than the one previously mentioned which is the
callasm 0x80E5075. This is the result.
Alternatively, if you want to skip the whole intro but don't want to skip the name selection, then you just have to write the bytes "91 10" in 08030440 and "31 16" in 08031100.
Also, Samu added a lot more of information on the Routines that composes the Intro.
In this post I only mentioned 11 routines, but he added 21 more!
So yeah, Professor Birch's introduction apparently uses 32 ASM Routines in total.
The details are in his post at Wahack which I linked up, if anyone's curious enough.