VAT and US citizens working in the UK

Does anyone know what the deal is with VATs and us US citizens?  I am thinking to purchase a computer and want to know if I can get the VAT back even if I work here in the UK? 
Anyone know anything about this?
-orkan

Technically speaking if you have a work permit/Visa in your passport you are not eligible to claim back VAT.

The rules that I know of are:

You have to be leaving the EU.
The goods cannot be used.
The purchase has to have been made within 90 days (check the exact time limit).
You have to have the goods available for inspection at the Customs.
You have to have a special VAT receipt from the store.

So for a computer, it would probably still need to be in the box in case they asked to inspect it.  They do look through your passport, so if they see your visa, your claim could be rejected.   

I would suggest you look at the conditions set out here (any claim outside of these rules is fraud & HMRC may well prosecute):

 http://customs.hmrc.gov.uk/channelsPortalWebApp/channelsPortalWebApp.portal?_nfpb=true&_pageLabel=pageTravel_InfoGuides&columns=1&id=VISITORSREFUNDS