The N900 is the undisputed king when it comes to the options available for tethering its internet-connection. The best part is that it works out-of-box without any software restrictions.
USB (Ubuntu 10.04)
With the USB connection, the N900 is recognized as a modem that can be used to “dial-in”. The setup is easy. The only thing required is the Internet-Connection info. Here are the steps to configure T-Mobile:
1. Connect the N900 and select PC Suite Mode (on the N900)
2. Left-Clicking on the Ubuntu Network Manager will display the N900 as ‘device not managed’. So cool!
3. Right-Click the Network Manager icon and select Edit Connections to create a connection.
4. Select Mobile Broadband. Click Add
5. Select the N900 as the Broadband device and follow the wizard.
6. On ‘Choose your Billing Plan’, select the appropriate plan (YMMV) and complete the setup. If your details are not listed, simply select a plan, complete the setup and fill in the details manually via in ‘Edit Connections’.
7. Select ‘Edit’ on the connection if you want to view or edit the setup.
8. Now select the connection to get online!
I have also had success with Nokia PC Suite on XP. I remember it being very simple and all that was required was APN info.
If this helps you, please let me know. The power of the N900 is not yet fully tapped here in the US. Why would anyone pay $15-30 extra/month to Verizon just for tethering on the Droid (without rooting/voiding warranty of course) ?