My tax code is 522L, this is my first ever job, i started 3 mnths ago. on my payslips says i pay 0 tax. why?

I have started working 3 months ago. this is my first ever job. I get paid 325 net weekly. My tax code is 522L and on my payslips says that I pay 120 pounds monthly for my national insurance but income tax says 0.00
Why is that? my employer is suppose to pay tax for me so i dont understand whats going on.
many thanks

Don't know what planet Trevor L is on. You won't have earned enough to pay tax for the year 2007/2008, which went from 06/04/07 to 05/04/08. You have a backlog of nine months unused tax allowance. Employer is correct.
National Insurance isn't done on a cumulative basis like tax. Each month is taken in isolation, and depends on earnings for that month only.
Am afraid the tax break will now be over with the start of the new tax year. Welcome to the world of taxpayers!. If ever you want to check deductions, look at www.listentotaxman.

Its because you've gone across two tax years. Last year you only worked three months so didn't earn enough to pay tax in that year, i.e 拢5220
You'll start getting taxed from next pay cheque, sorry :-(

a quick calculation using last years tax tables, your tax would be 拢44.13 and your NI 拢24.75, but this does not take account of Brown,s abolition of the 10% rate, which will probably increase your tax liability, or any change to your tax code for this year.
If my calcs are right, your NI at 拢120/ month looks a little high, might be worth checking.
EDIT, thanks for the vote of confidence from Steffi, but the figures i was quoting were for this year, based on last years tables, just checked them on this years tables, unless your tax code changes, there won,t be much difference.
Weekly tax 拢44.80 NI 拢24.20 or if paid
Monthly tax 拢194.4 NI 拢105.50

Its ok - if you didnt earn enough in the 2007-2008 tax year which ended 5th april.
You should expect to pay tax this month though.

The 522 means you have 5220 personal allowance. This is normally divided by 12 to spread it over the year. So you will pay tax on your monthly wages less (5220/12).
If your gross income was 1000 per month, thats roughly 拢113 in tax per month on average. It might be a little less this first one.