My AFCO told me to apply around xmas time as application takes around 6 months, so if i do that it should be okay.
In which case you'll be competing with all the lads/lasses who are graduating/leaving school in June 08, and those two groups probably account for 80% of the numbers applying.
Apply in September, when its quieter, would be my suggestion. You'll then get an answer in Feb/March, and if you really blow it, then you'll be able to start applying for graduate jobs in the milk round. If you succeed, you can then get an early bid for a place on IOT in September.