Cell Phones -- without "data" plan ?

I currently have 80+ AT&T smart phones
with data plans for employees to check their
Microsoft Outlook/Exchange email and want
reduce costs, but still allow employees
to check email if needed.

What options do you recommend so
I can cancel the "data" plans ?

Possible Options
 1. setup "email to text message" like http://www.craigharris.org/2011/03/06/access-important-email-on-cell-phone-without-a-data-plan/

 2. have employees connect to their home WIFI like http://www.christopherkois.com/?page_id=339

 3. do something like http://www.youtube.com/watch?v=bDVxz206mKk

 4. etc