Taxation , NI # and a new Job *help?*

Ok, I'm the first to admit I have no clue what I am doing!
I just got my FLR-M last week and am now able to work.

My question is, that when I start applying and going for interviews (and hopefully get hired!) what do I do about taxes? I'm living here in the UK, but I do still have a bank account in the US 8new york state* (which I use to pay my student loans with).

Do I need to tell my employer that I am paying tax in america (and er, at the risk of sounding even more clueless, how does that work? Does the company do that, or is that something I have to put aside like in a separate bank account?)I really really don't want to run afoul of either the IRS or whatever the UK govt has for taxation. I'd really appreciate links to other threads, and any personal experience folks have had.
Also, is there any sort of checklist of the things to be done for taxation/new hires/ that anyone knows of?

Lastly, can someone tell me how I get an NI number? (and what it is?) I've found it on a number of applications and some of the places I want to apply for positions at require it as proof of employablity?


Thanks!

http://talk.uk-yankee.com/index.php?topic=3119.0

this explains NI...

i'm not the best person to answer your questions on tax..

To add two points to meggles, an NI # does not prove that you are legally able to work in the UK.  It just means you can pay taxes.  Either your passport, or the letter you received with your FLR-M from Home Office should suffice in proving your ability to work in the UK.

What taxes you pay in the States will have no effect on the taxes you pay to your UK employer.  You will have to file your US return every year and in certain situations you will be able to claim deductions in both the UK and the US, but this will not effect how you are handled in the UK as a PAYE employee.

To add two points to meggles, an NI # does not prove that you are legally able to work in the UK.  It just means you can pay taxes.  Either your passport, or the letter you received with your FLR-M from Home Office should suffice in proving your ability to work in the UK.

Just to add, you cant get a NIN without proving you are legally able to work in the UK!