How will I then keep track of which LED was on?
Why do you need to?
for(byte b=0; b<10; b++)
{
digitalWrite(ledPin[b], LOW);
}
will turn off every pin defined in the array, without caring whether the pin was on, off, or out to lunch.
If you really have a reason to care, use an array of booleans. Set the proper position in the array to true when you turn a pin on, and set it to false when you turn the pin off. This way can be error prone, unless you twiddle the array only, then set the pin state based on the array.