If your company allows it, then simply log in to your BIS account (or set one up since you don't have one yet) and link your Yahoo account.
Verizon BIS is here:
https://bis.na.blackberry.com/html?brand=vzw
You should really check with your company IT department and verify that you're allowed to do this.
Even if you do get this set up... your company can always put IT policies in place to stop it from working.