XBee Newbie needs help getting started

What Paul suggested would go something like

union {
    unsigned long UL;
    byte B;
} myNumber;

void setup(void)
{
    Serial.begin(115200);
    Serial.println("Hello, world!");
    myNumber.UL = 0xBF30CF;
    Serial.write(&myNumber.B, 4);
    Serial.println("Done!");
}

void loop(void)
{
}

See output below, in Hex and ASCII. Note that the AVR is a little-endian machine, so the least significant byte of the number is first.