For me, the contractions came on fast and strong. I went in about 6am, then by 8 they had the picotin (sp?) .I.V going and shortly after that I started getting contractions. I swore by the pain of the contractions i'd have my little one by noon. Boy was I wrong. I got my epidural around noon I think....Then they kept checking my progress, so finally about 8pm they let me start pushing. Well I pushed for an hour and there was no progress, and my baby actually went back up instead of coming down further...She went so far up they couldn't reach her head anymore. Soooo after that they decided she was probably a little too big to come out naturally, so they took me in for a c-section. She was then born at 11:52pm that day. It wasn't really fun, because some medicine they gave me in the .I.V made me sick. I don't think it was the picotin tho...I think it was a pain med?
Then again, i've heard stories where people go in to be induced and have their baby with 5 hours....Or less. So it's really hard to tell how long your labor will be.