Open Question: No National Insurance Number?

I am 15 and will be 16 in August. I am in my last year of school and will officially finish school on the 30th of June 2010. So around a month's time. I am applying for a job in my local town, but I haven't yet received my National Insurance Number. It's supposed to be coming some time this month, however. Is it even worth applying for? Because I don't know if I can start work yet?