I finally quit smoking 6 years ago after many, many attempts.
The information in Allen Carr's book was a big help but a free iPhone app called LIVESTRONG MyQuit Coach finally worked for me.
Sounds silly but the app really helped with the support side of things as you could chat with a community of quitters.
Sadly I think it is only on iPhone as I couldn't find the app on Google Play store.
Good luck to everyone who is trying to quit.