Non-T-Mobile users can also use the T-Mobile G1 with the unlocking services available now. Android Community is running a giveaway of 3 unlock codes where you can unlock the T-Mobile G1 and use it on any GSM network. The contest is open to any registered Android Community member, you can read the contest detail here

While the unlocking service from unlock-tmobileg1.com cost $22.99 USD, you can try to call T-Mobile to get the unlock code directly if your T-Mobile account is active for 90 days. One member from Android Community says, “The G1 does *NOT* need to be on the network for 90 days, your T-Mobile account only has to have been active (with another phone or phone number on the same bill as the G1) for 90 days. I have my code and it is FULLY unlocked. You can call 611 to request and within 24 hours you get the unlock code for free via email response”