Thanks to flummer's response, I have the Sparkfun shield working with an 20x4 lcd display. I'm not using SoftwareSerial. I am using TinyGPS with flummer's modification to the cpp file.
Then use Serial1.begin(4800); and
while(Serial1.available()) // While there is data on the RX pin...
{
int c = Serial1.read(); // load the data into a variable...
if(gps.encode(c)) // if there is a new valid sentence...
{
getgps(gps); // then grab the data.
}
}