If this is a capability of your phone you can take the following steps. Hope this helps!
The Droid 2 doesn't allow for a different ringtone for different "corporate sync" accounts. This is a limitation of the MotoBlur Email app from what I can tell. There is only one place to set notifications and changing it affects all accounts.
Why Google allows anyone (Motorola/Verizon) to REMOVE functionality from the stock Android OS is beyond me. I can accpet having additional options and setting them as default, but not stripping it. The Moto Email app is nicer in a lot of ways than the stock "vanilla" email app... but if you need a ringtone for work emails that is different from home or another exchange account, then the Droid 2 DOESN'T where the Droid 1 did.
With a little searching I was able to find the Google email.apk file for the current version of FroYo. It installs and allows you to have at least the functionality Google intended. That said, the stock app isn't the best either. I want someone to come up with a way to show unread messages on the home screen for Exchange accounts.
Ben