HI,
We are interested to testing a new service provider Verizon instead of Nextel. Can a single user have multiple Blackberry's on the same BES. The resaon behind this would be to allow the user to test both Blackberry's at the same time.
Thanks for your help.

No, can't be done.
1 device per BES account at a time.

For BIS Plan, you are allowed to have only one BlackBerry e-mail address and up to 10 different e-mail addresses on single BlackBerry.

True, but I'm not too sure how that relates to this user's question.
BIS is not really related to BES, and the user also wants two devices on one e-mail account... not two e-mail accounts on one device.

You could duplicate mailboxes on the server and set up new mail to be delivered to both mailboxes but that's probably as close as you could get to what you're looking for. Would both really need to be tested side-by-side? You can just activate one and then the other and test each...

You could always set up separate user accounts and use different BBs, one for each account.

Is this question answered in the FAQ? It comes up a lot even in the Admin Corner.