I am testing the 4.5 os on my Pearl and the instructions in the first post of this thread has worked very well for me.

I have the $20 unlimited blackberry plan with TMO.

http://www.internettablettalk.com/fo...ighlight=pearl

Just as an FYI. Before 4.5 tethering with my pearl was very problematic. It would connect to the internet but browsing the web or almost anything else worked very poorly if it worked at all. I could sometimes get a page to load if I retried a bunch of times.