To cut a long story short, I need to get some money to my sister in the UK. I was hoping to get her the money from my Barclays bank account but because I don't have the pinsentry thing or a phone banking number they won't let me transfer the money. I think it is stupid that they don't let you do it online!

So now I have to transfer the money from my US bank account, I have never done a money transfer before what is the cheapest/easiest way to do it.

I will be transfering around $500.

XE.com?

I don't know about it being the cheapest, but the easiest/fastest is to simply go into your local bank branch and do an international wire transfer. I have used XE.com twice now, and both times its taken about 7 business days for the funds to arrive in the UK account. Versus, simply doing an international wire, the funds arrived in about 24 hrs.

Yeah, use XE.com. It'll take a day or two to set up an account (you need to provide proof of identity for the money-laundry regs which you can do by uploading scans of the required docs to their secure FTP site) and you may need to do some talking to your bank about setting up the transfer to XE's factors (Custom House), but once that's all done it's pretty easy, and generally they offer very good rates. There's been a recent thread about them here.

Xoom.com ?
don't know about them etc but it caught my eye the other day. $5 to send dosh.

Not used Xoom, but with XE you don't pay any extra for the standard service as they make their money on the difference between the rate they buy at and the rate they sell to you at, which is still usually much better than what a conventional bank would offer.

Another method I've used is PayPal, as I have two PP accounts, one linked to my UK bank a/c the other to my US. This is doable, but the rates suck and it was a lot slower than XE.

If it's not a huge amount you could send it with paypal, my mother sent me a small amount that way.

I use Xoom to send money to my daughter in the UK. It costs $5 per transaction which given the 9 hour time difference usually arrives in her account the next working day.
Never had any problems with xoom.

xe is the best option, but it takes time to set up...if you're in a rush, either your bank or xoom.com would be good options, xoom is probably cheapest though, especially for this kind of sum of money.

Just to update... I ended up using Moneygram at Walmart, it cost $9 and could be picked up in te UK instantly (well 10 mins later). It was really easy to do.

I just had a quick look at the website.. where do they have locations in the UK, to pick up the money? Is it in ASDAs?

They certainly used to have an agreement with the Post Office and you could send and receive through any post office. Not sure if that's still the case.

When I looked at the moneygram website they quoted me something like $30 just the do the transfer!!! A far cry from the $9 that Walmart charged. I thought there would have been a pick up in ASDA too because they are owned by Walmart but ASDA do not do it.
My sister collected the money from the Post Office, all she needed was her ID and the reference number they gave me in Walmart... I actually found the process very easy and I didn't think the $9 charge was bad at all, considering it is pretty much an instant transfer.

Forgot to add, Thomas Cook Travel agents are also listed as Moneygram agents so she could have collected the money there too.

$30 is about what I would have expected from someone like Moneygram or Western Union but perhaps you got lucky and got some promotional rate from Walmart - or perhaps Moneygram have decided that it is better marketing to charge low fees and make up the difference by using a really bad exchange rate ...

Whether it be a small or large transfer ensure that you look at using a currency exchange specialist. No fees and a great rate of exchange will save you money.