Today, I took a 7 person company and moved them from a shared Linux/POP server to Google Apps. Once I got the process down, it was super easy.
Presuming that you want to keep Outlook in use or use the gmail webmail as your primary interface (which is what it sounds like Google wants you to do), you start the same way.
Start with the Google Apps Sync for Outlook:
Just install that, log in, choose a new profile. and then import and choose the old Outlook profile where all the data is. It'll take a minute before it starts importing, but it'll do it.
This is really the best method. I tried to do an import from a PST file, but that failed several times. The google email updater is also an option, but that requires Outlook to be closed, so it's not convenient for a user to work on while the uploading process is happening.
I also had to set up three Blackberries. Setting up Google sync (which does wireless syncing of calendar and contacts only) was super easy. Just go to this site on the BB, log in, and that's it:
But what was weird was the Google Mail app for Blackberries. You can get that here on the BB:
On the Storm, I was able to get the Google icon to appear. On the 8800 and the 9630, I downloaded and installed the mail app, but there was no Google Mail icon. I installed again. Nothing. So instead, I set up those two BBs with IMAP accounts.
First, I had to enable IMAP. You can't do that on an individual's Google settings. It must be done from an admin's console.
Here's how you enable IMAP company-wide:
Click on Manage this domain
Click on Service settings
On that page, find the check box for "Disable POP and IMAP access for all users in the domain" and UNCHECK that box
Wait 30 minutes and you'll be able to use IMAP to check email for staff on google apps