The tethering setup has not changed in years. It's still the same and works great on 3G.
http://www.blackberryforums.com/blac...em-laptop.html
As for speed, it looks decent.
Not too shabby. This is USB tethering to my Vista notebook from the Philadelphia T-Mobile 3G network. Funny though, gave me an IP address somewhere out in Kansas. lol
On average seeing about 1mbps down but it's not a smooth consistent stream yet. T-Mobile needs some tweaks on the network setup. I see bursts of 2+ mbps and then it can fall below 100kbs. Good app buffering saves you but I think TMO can get a smoother experience.
Slingplayer to my home was fairly decent. I was seeing about 650k-750k range on streaming. Not too bad and better than most public Wifi hotspots. (TMO Hotspot in the SFO airport only gave my 250kbs on my 8320 via my curve as a WiFi modem)
Slingplayer Mobile (ver 1.0.0.2) on the 9700 itself played flawless at highest video resolution setting. This is nice! Pocket TV on the go.
The only issue I had was that Nobex Radio couldn't connect but everything else did including Pandora and Slacker.