I won’t link to any of these as no doubt some of them are scams but… If you do a search on ebay.com for “Google Android Unlock” you’ll see that people are already offering unlock codes for the G1 if you send them your IMEI. Whether these people can genuinely offer this already may be doubtful but there is a chance they have a link into an application or person from HTC or T-Mobile which / who can provide this.

There are also unlocked G1’s being advertised in the UK via places such as craigslist. Personally, I wouldn’t go near these at the moment but I’m sure there will be some more legitimate sources of SIM free devices in the near future. Alternatively T-Mobile may provide the device at a price with a pay as you go option, which as I highlighted previously would be great for developers or people who are just curious to try the device out mainly on wifi.

I have read that in the U.S. the 3G on the G1 may not work if a T-Mobile G1 was unlocked and an AT&T SIM was put in the device. I don’t see any such issues being prevalent in the UK. You should be able to unlock the device and switch out the SIM easily enough to O2, Orange, Vodafone or 3 in the UK

However, it will be interesting to see if T-Mobile uses a specific APN for the G1 to restrict access to services for people using other SIMs. This could stop ‘jailbroken’ / unlocked G1’s from getting access to items such as over the air updates (which have been pushed out already in the U.S.). However, this would also limit access to updates for people using the device over Wifi. For that reason, maybe they will look to use a different method such as a T-Mobile sign on to try to encourage users away from unlocked devices.

I’ve mentioned previously the need for developers to have an Android device which isn’t necessarily tied in to a contract. It will be interesting to see if T-Mobile provide this as an option in the UK. Their website certainly suggests that the G1 will work with a Pay as You Go SIM (click here and expand the ‘legal stuff’ section).

We’re giving away 8 T-Mobile G1 phones with a T-Mobile Pay as you go Talk & Text SIM card (see http://www.t-mobile.co.uk/shop/mobile-phones/price-plans/pay-as-you-go/ for details) loaded with £25 top up credit. Just remember that you won’t be able to access our highest data network speeds unless you upgrade to a pay monthly price plan. Also, as your G1 has an “always on” mobile internet connection, you will pay up to £1 a day for our web’n'walk service, see http://www.t-mobile.co.uk/shop/mobile-phones/price-plans/pay-as-you-go/ for more information.

T-Mobile 'Pay-as-you-go' prices

So this suggests that the G1 will run on a pay-as-you-go SIM but at limited speed and with fairly hefty prices for data use. However, the G1 has wifi built in so this probably isn’t such a concern for developers who only want to do occasional testing on a ‘real’ data connection.