DS1 - waters broke, didn't go into labour, induced 24 hours later, 7 hours after induction he arrived.
DD1 - my DMum was on eggshells telling me that second labours are quicker, I didn't believe her. Woke up at 5.30am with what I thought was a stomach upset, noticed cramps were coming and going so decided to go in shower to see if that helped. 6.50am decided to ring labour ward just in case, they told me probably early stages of labour, have two paracetemol, go in bath, "you haven't been going long so you'll be ages yet". Woke up DH, who took one look at me crouched on floor and told me I was going to hospital. One white knuckle car ride later, arrived at labour ward at 8.15am. MW told me to go to triage as would still be early stages, I shouted that I could feel head and needed a delivery room, DD1 born without any pain relief (no time) at 8.43am. Up and about 30 mins later, was brilliant.
I have been told that should we decide to go for DC3, I should consider a HB, and have to go to hospital if I want a hospital delivery as soon as I feel first contraction, as labour likely to be even quicker. 
So, things to bear in mind - have all your stuff ready so no last minute panics, and if you don't have a HB go to the hospital and demand an exam, even if MWs are telling you it can't possibly be later stages of labour. Also be prepared that you might not get pain relief that you would like - I was really panicky when they told me I couldn't have an epidural because I had been relying on one.
Was interested to read further up thread about delivery of placenta being difficult after fast labour - I had injection (just about had time) and it was really difficult. They really had to tug it out, much more difficult to deliver than after DS1. DD1 came out more easily than placenta, actually.
Good luck! Let us know how you get on...