Pending fatherhood is turning FOO FIGHTERS star DAVE GROHL soft - he's hoping to write piano lullabies. The rocker insists he'll be using the piano his wife bought him for his last birthday to create tunes - and he'll be using his baby, which is due next month (APR06), as inspiration. He says, "I've never played piano, and I've always wanted to. I taught myself how to play every instrument that I play. I've never taken lessons. "Just before my birthday, I sat down and started to figure out how to play piano, just by ear. I'm not f**king Liberace, but I'm figuring it out."