Methods of paying the IRS

Last year I cashed in a 401k and exersized some stock options, so my US tax bill this year is pretty steep.  I don't have any bank accounts in the US any more, what are some methods of getting the money to the IRS?  Last year I just owed them a little so used www.pay1040.com [nofollow] , but the amount this year makes that impractical.  Can I do direct electronic transfers?

A banker's cheque from your regular UK bank is fine.  The US will accept these when the amount is big.  The banker's cheque should be in US$$, not in ££.

Most UK banks offer a dollar account.  Open one with a few dollars (not the whole shebang!).  Then hire a Currency Exchange company to arrange the transfer - argue for 30 basis points or less, no fee, no commission.  I can provide a few recommendations offline.  The currency exchange will take ££ and convert to $$, depositing it into your $$ account.  Your bank will then arrange a banker's cheque for the $$.  This will save you $100's of costs from your bank for the joy of paying your taxes.

Thanks!  A quick check on my bank's website shows that they do have dollar acounts available.  I think I should be able to avoid any currency exchange headaches too.  The cash for the US options I exercized are sitting in a holding account at the broker.  I could transfer those dollars to my new dollar account, and pay off the feds.