Sorry to resurrect an old thread, but there a couple things that could be changed in your code that might benefit the speed. I'm not sure how Serial.write() handles ints, but it is designed for bytes. You should change mapVal to be a byte in the first program. The second change would be to add a couple millisecond delay to the transmit side loop. Transmitting a byte at 9600 baud takes around a millisecond. Reading an analog pin and doing a little math most likely can be done much quicker. A 2 or 3 millisecond delay will keep you from overflowing the buffers, and will not create noticeable lag.
int val = 0;
byte mapVal = 0;
int potPin = 0;
val = analogRead(potPin);
mapVal = map(val,0,1023,0,179);
For the sake of efficiency, you should change servoValue on the receiving side to be a byte as well. An 8-bit processor such as the 328p in Arduinos can process 8-bit numbers much faster than 16-bit numbers. It probably wouldn't make any noticeable difference in this program, but optimizing like this can be very important in time-sensitive and complex programs.
As a side note, you don't need a semi-colon after an include statement. This is because includes are handled by the pre-processor, which is the same part of the compilation process that removes comments.
[code]#include <Servo.h>; /Unnecessary semi-colon
#include <Servo.h> //Corrected