I am Bold user and here in Singapore subscribe to Singtel Blackberry service, unlimited plan.
Just to share, I have successfully configured to use Bold as modem for surfing internet on my laptop by using the instructions (attached). But yet to verify if Singtel will charge for additional data usage on top of my unlimited plan. I didn't specify +cgdcont=1,"IP","<your Internet APN>"
and i leave userid and password as blank when dialing through the modem.
If anyone here (especially singtel user) have similar experience, please share with us