It is out of print - as it is being revised for JAR. The old copy is available from the library - cos I went to my local library and they got it sent down to me from Aylesbury.
To be honest, having just completed the IR, I didn't find the books very much help - the schools teach it differently.
Best tips I can give you:
- study the IFR charts
- study the approach plates (really understand what they are saying...e.g. look at Exeter ILS plate and see if you can spot the 4 major differences that approach has)
- get the a/c checklist and learn it
- practice on a Flight Sim, using the checklist at the same time.
All of this was much more useful than the book, although I read through it 5-6 times.
Good luck!