Well I have somewhat the same question, so I will try to wake up this sleeping thread 
Yikes - over three years old!
A am going to try to move from MicroChip PIC and MPLAB IDE to Arduino and the Arduino IDE.
I am using Ubuntu Linux version of the Arduino (0018) IDE, RBBB, BBB, and USB-BUB boards.
I have lots of experience with PICs and MPLAB. Mostly with assembly language.
I look at the manual and help for Arduino IDE help and I don't see an easy way to put assembly language in with the Arduino Ccode. I have some applications that I am sure will require the precise timing and speed of assembly language. I would like to write a mix of C and assembly and be able to call functions written in assembly from the C functions.
Is there an easy way to add that functionality to the Arduino IDE?
I would appreciate it if someone could point me to the information that I need to do this.
Thanks,
Walt Bankes