I use a Google Apps e-mail address (i.e. it's tied to my domain) and GMail can work with this fine, but when I tried to purchase something from the Market it said it can't use this and I need a googlemail e-mail. I have one so I entered that, but now I want to use one I have set up especially for this purpose but I can't see how to change this relationship. If I stick a different SIM in, the Market now asks me to confirm the account password but it won't let me change the actual address. Does anybody know how to change this? I'm running 1.5 on a T-Mobile Pulse. Cheers
Try going to google.com from a regular computer and signing up for a google checkout account using your google apps e-mail address. While you're there, you can store your credit card info in your google checkout account (I feel safer doing that from a secure PC than over the air from my phone). After you setup the google checkout account, maybe then the market will allow you to use that account/email address for buying apps.
