I have read all the instructions and can't seem to get bluetooth tethering to work.

Here's my setup:
N800 - upgraded to OS2008
Treo 700p - Sero Plan with data

What I did:
I installed the tethering hack. I got the Treo and N800 bluetooth connected, recognize and trust each other. Once I did that, the N800 ask me to create a connection. I selected USA, Sprint. I tried to connect. I left the username and password blank. I get a "Connection failed" message. I read I might need to try a couple a times. Didn't work. I tried entering my pcs vision login. Connection failed. I tried to edit the connection and change the connection type to "Data Call" as some people mention. If I do this, the N800 won't let me use #777 as the dialup number. The # is greyed out. I left it as 777. I tried to connect. The status stays on "Connecting".

What am I doing wrong??? Please Help!

Did you follow the directions at this site:
http://vocaro.com/trevor/treo-dun

I'm trying those right now with my 700p (with the full Vision Plus plan).

Will post the results here once I get through the setup of it all.

cheers,
Etienne