You need to look on the LEA section of your local/district council which should set out the timetable. My memory tells me it is Feb next year but I could be wrong.
It is definitely worth looking on the LEA website asap - the general admission criteria should be there for each school. This is important if, for example, you wish to enter a faith school (ie start going to church pronto) etc. Also make sure you put down second and third choices - dont just stick with first choice. If first choice is over subscribed you will just get allocated anything so be sure to make 2 and 3 place choices.
just hd a look on the website and it's a natioanl timetable - opens on 1st september 16 and closes 15th jan 17. I'll also dd go and look - i thought i knew which schoolswe wanted before we went to see them!