There's many ways to get IP-Relay on a BlackBerry, either by adding "HipRelay"/"SipRelay"/"My IP Relay" AIM buddies to your AIM chat. These are relay operators standing by over the AIM chat network. Just install VeriChat or another 3rd party program.
For realtime keypress-at-a-time, use a telnet client to access telnet://wireless.ip-relay.com:2510
... I use Idokorro MobileSSH for this.
Yes, please look through this: Benefits of BlackBerry for the Deaf & Hard Of Hearing
And my "BerryFAQ" link below: