Just want the answer? See below
Although I run my own personal Exchange Server at home, I also run a couple of Google Mail accounts for subscriptions to online forum sites, newsgroups and suspect sites I might be required to sign up to occasionally. I’ve been caught in the spam trap before and I’m triply cautious not to share my main email addresses with anyone I don’t trust. Maybe I’m just overly cautious… but an email address is something you should treasure.
When I used Gmail for the first time, it was obvious Google had it right: for a free mail service for the average home user, it just works. You’d be hard-pressed to use all your 7.5GB mailbox quota (an ever increasing figure) and features like conversation view (recently introduced in Outlook 2010, thank you!), labels and archiving are handy.
However, I was never impressed by the email domain I received. Other parts of the world had the privilege of @gmail.com, yet a registration attempt from the United Kingdom for the past few years forced the longer googlemail.com at me. my alias@gmail.com still worked, but outgoing email and Google themselves still used the longer name.
You might ask: Why?
The answer goes back to a trademark dispute with an agency in the United Kingdom in 2005, which forced Google to drop gmail.com for new UK registrations. The webmail site was also rebranded for UK users with different logos. However, Google and the other party agreed to settle the dispute for £228k in 2008 and the rebranding back to gmail.com is now taking place.
I’m an existing customer. How do I get my @gmail.com address?
If you currently have a googlemail.com email address and want to use gmail.com as your “primary” address for sending mail from, you’ll need to convert it. Ironically, I hadn’t heard about this story until I accidentally stumbled upon it in Google’s Settings and I’d wager many, many users are in a similar position.
To claim your address, log in to Gmail, click Settings in the upper-right of the browser window, then select the Accounts and Import tab. Choose the Switch to @gmail.com option to begin the process. Per typical Google fashion, it’ll take you a matter of seconds.
Rest assured your @googlemail.com alias will still exist and be routable; you won’t need to re-register with any sites or send out mass “I’ve changed my address” messages to anyone who currently reaches you on that address. However, any mail you now send will come from you@gmail.com, not you@googlemail.com, a significant improvement in my opinion!
Thanks once again, Google!

