This is a nice post, I've picked up from: http://www.pureblogging.com/2007/05/31/move-your-emails-to-gmail/
Its about transferng or using our existing domain with gmail:
I understand if you don’t like to use E-Mail clients like Outlook, Thunderbird etc. You are always on the move, you are a blogger! Not an office rat
Now this trick on how to use your domain email inside Gmail is a quick and dirty one. I’m sure most of the readers will agree with me that Google’s Gmail service is an awesome piece of software. Almost no spam, intuitive and yet simple GUI, great use of tags instead of folders etc etc…
So let’s see the list of things needed:
A domain name for your blog
Access to your Control Panel at your ISP
If you have the above listed things that means you are ready to go. Now, login to your domain’s hosting Control Panel and make sure emails coming to email@example.com is forwarded to firstname.lastname@example.org account. Afterwards, login to Gmail, go to your Gmail Settings on your top right corner of your browser. Pick Accounts tab and click on Add Another email address. In the popup window type in your name and your email@example.com email. Click Next Step button and in the next screen click on Send Verification button when you are sure you have made no mistakes in typing your email address.
You wait for the confirmation code to be sent to your Gmail account (remember we redirected all incoming emails to your Gmail account?) . Once you receive confirmation email from Gmail just follow the instructions written there and follow the long link they sent to you.
At this point you have emails sent to firstname.lastname@example.org and you can sent email in behalf of email@example.com.
To see if this really works try sending emails from other emails, for e.g. Yahoo!, to firstname.lastname@example.org and see if you receive. Then reply to the message to see if sending is ok.
Make email@example.com account as default. This means whenever you write email it will be sent from your firstname.lastname@example.org account.
Create a filter based on Sent to address. This helps you to separate emails coming to your blog email address and your original Gmail account.
So if you have a domain name it’s time to use your emails from it!
Note: It won’t however totally replace your email needs, if you want more take a look at Google Apps for your domain. I am myself moving there actually after having used the above trick for 3-4 months now.