The steps I found on the ‘net seems to work.

Remove the SIM card from your iPhone and insert it into the Google Android developer phone. When you start the phone for the first time, when the phone asks for your Google account, you need to press the menu button, and select “APN”. Add a new APN entry on the Dev phone with the following settings:

Name: att
APN: wap.cingular
Password: CINGULAR1

All other fields are left blank. Click menu, save, then work your way back to the login prompt, and sign in as usual.

It appears the good news is that once you get the phone set up, it will operate (albeit without phone or 3G wireless) without the SIM card, which makes the phone useful in a limited fashion for development. And if you do need to test the card on 3G, you can just move the SIM card back–though unfortunately it’s a real pain in the ass to extract the SIM card from the Google phone without tweezers. (On the other hand it’s impossible to remove from the iPhone without a pin, so I guess they’re even.)

h/t