I was cut as opposed to tearing, and although it is still sometimes tender it has healed well. My friend's labour was so fast that she tore from front to back and it took a long time to heal. I think it all depends on your skin type, the length of labour and how baby is positioned.
However, I have a friend who insists that you should "rub wheatgerm oil on your noo-nah to prevent tearing. So there you go, you heard it hear first folks.
Also, although I never did this, I remember reading in a pregnancy book that in the last few weeks of pregnancy you can.... aherm.... stretch yourself down there by inserting your finger(s), maybe when in the bath or something, probably not a good one to try when at the bus stop and it can help to stretch / prepare your vaginal opening for the birth.
I took raspberry leaf tea at the end of my pregnancy and although I have nothing to compare it to (first baby), I can't say that it helps that much, although God knows what it would have been like without it LOL
Lastly - am I being dim - how on earth did she manage to tear hear labia during childbirth?