Google Apps is the private-label version of Google's Web-based office suite. The "from" address on your e-mail is your own domain, rather than Gmail.com. Google Apps includes Google Docs, Google Calendar, and more. It has an administrator interface for managing multiple users. Google Apps comes in a free version, or a $50 per user per year Premium version, with tech support and increased e-mail storage quotas.
I've used Google Apps as my main work and personal e-mail for most of the past three years, and I've been happy with it overall. However, you should consider the advantages and disadvantages before making the switch.
Advantages: It's convenient. No need to worry about messing around with POP3, SMTP, and IMAP settings on multiple devices. Just point your Web browser at Google Apps, and you're good to go.
You can still use a desktop mail client if you want to, but I don't know why you would. Gmail's Web interface is the best e-mail client available.
Gmail is very reliable.
Spam filtering is fantastic.
As you might expect, the search is first-rate--it's one of the reasons I went back to Gmail after my brief flirtation with another e-mail provider earlier this year.
Disadvantages: Regulatory issues might be major obstacles. If you work in heavily regulated industries, such as healthcare or finance, talk to your legal department about whether going to Google Apps would be legal.
Privacy is another issue. As my friend Gina Trapani, author of The Complete Guide to Google Wave, says, everyone must make their own decisions about how much they trust Google. On the whole, I think Google has behaved in a trustworthy fashion with the information we entrust to it. However, if you're squeamish about giving that much information to Google, I'm not going to argue.
Some people don't like using Google for Gmail because they don't like giving up control of their own e-mail. But that doesn't make sense. You already don't have control over your e-mail as it's traveling over the Internet. Gmail has had outages, but no service is perfect, and Google has shown itself to be pretty reliable.
Also, if Gmail does go down, it's usually a newsworthy event, so your business associates might be more understanding than if your e-mail goes out because you accidently dropped a raspberry smoothie on the server.
Another thing to keep in mind when considering going to Google Apps: When Google is upgrading Gmail, Google Apps is the last to get the goodies. Google Apps still hasn't been integrated with Buzz. Google Apps users got the spiffy new iPad interface for Gmail weeks after regular Gmail users got it.
A couple of final tips: You can upload your existing e-mail to Google. On Windows, use the Google e-mail Uploader for Outlook 2003 or later.
On the Mac, make sure you have Apple Mail configured to connect to your old e-mail account and your new Gmail account using IMAP. Simply copy messages from the old e-mail account folder to the new one. And you're done.
Tip for Mac users: Mailplane is a $24.95 Mac client specifically for Gmail. Its core is a Web browser customized for Gmail, and it adds features like notifications for new mail, the ability to make Gmail your default mail client on the Mac, simultaneous logins to multiple Gmail accounts, and more. I've been using it for more than a month now, and I like it a lot. Finally, a tip for iPad users: The spiffy new custom Gmail interface for the iPad is a bit flaky. Sometimes it seems to stop responding entirely. And the standard Gmail interface is worse. I've found the Basic HTML interface is most reliable, while the custom iPad interface is most usable--when it's working. You can switch between Mobile, Desktop, and Basic HTML views with a row of text links at the bottom on the Gmail window.