GnuBox is a small, free software that allows you to access the internet from your phone using your computer's internet connection - without paying any fees (like GPRS) to your operator, and at speeds up to 400 kbit/sec. You can use Bluetooth or the USB cradle for connecting to the PC.
This has existed for Nokia phones for a while, but not for SonyEricsson P800/P900/P910. Now a new version is available for devices using UIQ 2.0 and up.
Some 3rd party apps (like Opera) were working out-of-the-box with PC suite, but not the bundled applications (Messages, SyncML, etc.) They do work with GnuBox.
Source code, SIS installer, detailed installation instructions, faq and troubleshooting tips are found at http://gnubox.dnsalias.org/gnubox
(Step-by-step install instructions for: linux PC using USB or Bluetooth with BlueZ drivers, windows PC with USB or Bluetooth over WIDCOMM drivers, WinXP drivers or Fujitsu Plugfree drivers. Should work with other platforms though.)
Please do not reply here, go to the same thread in the P900 forum: http://www.allaboutsymbian.com/forum//forum/thread/32376/