SoftwareSerial is obsolete. You should be using NewSoftSerial, instead.
pinMode(rxPin, INPUT);
pinMode(txPin, OUTPUT);
Do you want the software serial instance to manage these pins, or do you want to? It shouldn't be both ways.
// toggle an LED just so you see the thing's alive.
// this LED will go on with every OTHER character received:
toggle(13);
That comment is plain wrong. The LED will be toggled every pass through loop, regardless of whether there was serial data read, or not.
char someChar = mySerial.read();
// print out the character:
mySerial.print(someChar);
If nothing was available to read, mySerial.read() returns a -1. How do you fit that into a char? Why do you want to print garbage if there was nothing to read?