You can Get started with Google Apps for free with up to 10 custom user accounts. To learn more go to:http://www.google.com/apps/intl/en/group/index.html

This way you can set up your email as me@mydomain.com

If you have multiple email accounts, but want you to manage everything in one interface you can accomplish this by either forwarding the other email to me@mydomain.com or use POP3 to download the email into your gmail account.
mail settings > accounts > Add a POP3 mail account you own

You can also “send mail as” another email address if you like .  
mail settings > accounts > and add anther email address to “send mail as”

I find that Gmail works GREAT for business!

@amyhallbiz – LOL I don’t know about all that. But I have set up quite a few gmail accounts for clients, and I also get the “how to” or “help” calls.