even if you're on a BES you can still configure additional email accounts to send mail to your BB. This is done with the blackberry web client - the user creates an account online where his address will be (for instance)
![[email address]](http://www.blackberryforums.com/?emailimage=24b157c68d289bf39ae1f2afe9ce3b1e)
and sets up his other POP3 accounts to send email to his blackberry. Wiping the handheld won't work - you probably need to have the SIM card re-provisioned or get a new SIM card.
Hope this helps!