To answer the vague question with a vague answer, yes it is -possible-.
The question is, will it have the features and functionality your client is looking for? Being able to accomplish this will greatly depend on how your client is trying to connect (i.e. via a provider or through a corporate setup), and what access you or your client have to authenticate. Then you have to consider the UI or interface to make the connection from the phone to the provider, which right now, I am not aware of on that exists for the Blackberry (will ask some coworkers).