Hi Kerryn,
A retroverted uterus simply means your uterus is on the wrong side. It's very common (i have one - so does my mum) and often doesn't have any side effects. I've had problems with it (it so retroverted that it was virtually sitting over my vaginal canal and being touched by partner's penis during intercourse - ouch) so i've had to have the ligaments behind it operated on to try and make it sit further back. A close friend has had the same thing so if you've ever felt a lot of pain and/or nauseous during intercourse, blame it on the retroverted uterus!
As for labour, i'm not too sure to be honest. I think i remember my gyno saying that it can have some implications but as i haven't had any children yet, i couldn't be sure.
Hope that kinda helps! Good luck.
LM