Which is a good reason to go for the O2 prepaid sim, as it DOES roam in the US.

Inst Virgin UK on the GSM Network???

Here in the US they are on the SPrint CDMA Network... So unless Virgin has a deal with one of the 3 GSM providers I don't see how Virgin UK will work here...

Yes, Virgin is GSM, and yes, they DO roam on many other GSM networks, including some in the US. Just because Virgin in the US is on Sprint doesn't mean they can't make use of roaming on another US GSM network.

ROTFLOL Then again Scott, weren't you the one advocating the Swisscom pre-paid card that we used to track down certain Al-Qaeda principals? :D

The T-Mobile UK prepaid works pretty well too in roaming. The downside with the UK mobile pre-paid SIMs is that the rates are in pounds, a currency which remains stronger and more stable vis-a-vis the dollar more than the euro. A non-pound denomination will likely be cheaper per minute than a pound sterling-denominated one.

I have roamed in several European countries with my Vodafone (UK) card. It isnt cheap but it is probably comparable to the deals people are finding on the web. When I put it in my phone in the US it shows that it is working. I havent tried using it for voice. I sent my self a couple text messages. Still waiting for them to arrive. It might not work in the US. But I have used it no problem in France, Italy and Spain.

Well the sms I sent with my prepaid Vodafone UK SIM card from here in SAN worked when sent to my TMobile US postpaid account. So apparently you can use Vodafone prepaid cards in the US. Interestingly, the SMS I sent to my Verizon wireless phone hasnt come through yet. I will try again later. I entered the number manually, perhaps it had a mistake.

Btw, anyone here tried the International Sim card (forgot the name) that has a number based in Monaco?? I always wanted to buy it, but then you have to shell out $79 for the card then buy a $100 worth of credit....

Lol

Not really worth it considering UK and other european sims do pretty much the same or even more.

Unless of course you want a cool "home" number :)

Overdeveloped Monaco is not for me -- unless someone wants to help me seize a certain picturesque castle in a behind the scenes political coup; what was the name of that not so bad looking "princess"? :D

Virgin Mobile UK rides on top of T-Mobile's GSM 1800 network in the UK.

http://www.gsmworld.com/roaming/gsminfo/index.shtml

Indeed, you can pick up a Virgin starter kit at Virgin Megastores or at Cellphone Warehouses, which are about as ubiquitous in the UK as McDonalds franchises.

If you're really hung up on getting a SIM with with Top-Up card before leaving the US, lemme know with a private message--I may have a Virgin starter kit still in box with 5GBP on the card.

I think expansys.com also sells prepaid cards for good prices compared to the internet sim card sales places. But both LHR and LGW have The Link stores inside the airport that sell starter kits for Virgin Mobile, Vodafone and I assume the others as well. Something I found out today is that the Virgin store in the duty free area of LGW sells Top up cards for duty free prices. They are about 15% off face value as I recall (its been a long day).

Interesting. I wonder if Heathrow is the same thing at the stores that sell top-ups (presuming you already have a card). For the entrepreneurial youth out here, 15% off could make a good business for someone getting refundable tickets and topping up people inside the duty free area. ;)

UK Virgin prepaid will roam onto Vodafone here in Australia. Well mine does anyway!

Can anyone significantly beat http://www.hopmobile.com/explore_costs.html at $0.95/minute outgoing, $0.35/minute incoming, $0.10/SMS message?

Also, does anyone know about using GPRS (with a laptop) while roaming on any prepaid cards?

Depends completely on the country you will be in. That is a good deal in some, and terrible in the UK for instance (20 pence outgoing, free incoming). Also, if you are buying that card from an internet provider, not directly from the phone company there may be a very significant mark-up. So while you may pay on the card $0.95 cents per minute, you pay for instance 50% or 100% more than the face value to purchase the card. So your real cost is more like $1.50-$2.00 per minute for outgoing calls and $0.55-$0.77 per minute for incoming which is more than simply roaming on a US or UK card would likely cost. I dont know about where you are thinking of purchasing the card but I know that some of the internet places do this, quote a reasonable price per minute but that isnt the real cost you pay but rather the cost billed by the phone company, not taking into account that you may be paying $100 for a card with $50 of call credits.