Documentation. Wi-Fi for Everything. Technobly/SparkCore-LiquidCrystalSPI. LiquidCrystal & Shift Register - Spark. I'm currently testing this with the SPI mode of the Adafruit SPI/I2C LCD backpack... it basically makes the wiring easy.
However you have to flip rewire the code for EN, D4-D7, as those are wired differently than the Fritzing diagram I made above. That said, it wasn't working at all.