I also tried with with second baby and it worked, IMO.
With dd I had gas and air, pethidine and epidural.
With ds, has gas and air for the last half hour of labour. Recovered quickly, lost aby weight, felt positive and much much much less tearful.
I know this might have happened anyway - but I'm sure it helped.
What also helped was ante-natal yoga. I also had a homeopathic birth kit.
Basically after having a tough time first time round, I was determined to do anything that might help me cope better with the second labour, especially as I was keen to have a home birth.
Was having a terrible time sleeping from about 32 weeks pregnant. Went to see the hypnotherapist at 35ish weeks, desperate for sleep. She did a session where she talked about images, my first labour, what I wanted to happen and so on. Then I had a second session a week later that she taped, and I listened to that tape nightly until I went into labour. Instantly my sleep improved drastically, and the tape helped me relax and have good midday naps (dd permitting!) and todrop off easily at nighttime.
She talked in the tape about all matters post-natal as well as the birth itself - i.e. you will be confident, you will feed easily, you will eat what you need and be nourished and healthy and so on.
So would recommend it - but would also suggest that ante-natal yoga is at least as useful practically because you learn breathing techniques and about different positions for labour that can help take your mind off the contractions and make sure you get the best possible birth, all things going well.
Because I had a very quick complication free labour, the homeopathic kit was mostly used post-natally - arnica for healing, something else for afterpains and so on.
Good luck!