Useful links and forms
Form 4868 Application for extension
http://www.irs.gov/pub/irs-pdf/f4868.pdf
Form 1040 Individual tax return
http://www.irs.gov/pub/irs-pdf/f1040.pdf
Form 1040 ES Estimated tax for individuals
http://www.irs.gov/pub/irs-pdf/f1040es.pdf
Form 8938 Statement of foreign financial assets
http://www.irs.gov/pub/irs-pdf/f8938.pdf
FinCEN 114 Report of Foreign Bank Account
http://bsaefiling.fincen.treas.gov/NoRegFBARFiler.html
Embassy of the US in London
US UK tax treaty
http://www.treasury.gov/resource-center/tax-policy/treaties/Documents/uktreaty.pdf