I'm signing up at Zecco.com — in the application they ask if I'm subject to backup withholding. I've searched and searched but I can't figure out exactly what I'm supposed to answer as a non-US resident. I know the W-8BEN form is related to this somehow, but I'm not entirely sure what I'm supposed to do.

Hopefully this will help:
W-8ben - UK Small Business Forums

Thanks Brian, that's really helpful!

thankssssss

Oh, and to sum it up for anyone else in my situation — Unless you are withholding US taxes (unlikely) then the answer is "no".

And any non-US residents fill out a W8-BEN form to send off to the trader along with the application.

It's just to say your own country will take care of taxing you for any earnings from trading US companies, otherwise it gets complicated with the US taxing you.

Indeed - as your income is drawn from the UK, UK tax regulations apply - but US companies have to ensure they are covered for tax purposes, ie, not seen to be evading tax.

1500 seems plenty to me. Most trading websites require $2500 investment and £1500 is roughly $3000.

As a trading website, I just signed up at Zecco.com - Free Stock Trading & Investment Community and couldn't recommend them enough. They're also free. But they're mainly for US companies, if you wanted to invest in UK companies you'd need a UK trading company.

For looking up stocks and keeping track of my portfolio I've found Google's finance website very helpful.

Do you know what kind of long term investments you're looking at buying? I could give a couple of suggestions for you to look into if you've got no idea. Although I would recommend investing in what you know a great deal about!