If you haven't gotten the new Google Notifier you should go get it now. Not just for Gmail anymore, it keeps you aware of what's happening on your Google Calendar too.

Probably the bigger news is Google Apps for Your Domain. Basically, this means you can get the power of Gmail and Google Calendar to run specific to your domain. Instead of having your @gmail.com address, with Google Apps you could have Gmail power your @yourcompany.com email address. You can do the same with Google Calendar. Only users in your company sharing a private calendar hosted by Google.

For a lot of small businesses (plexus included) this is an appealing alternative to Exchange.