Yes, it is now possible!
A few things to note first of all. THIS IS NOT OFFICALLY SUPPORTED!. I have it working with a Vodafone SIM with blackberry.net APN enabled and a Vanilla P910i using the Web Client Software.
First download this zip file from Sony Ericsson.
Once you unzip the file, you will need to install the .sis file onto your P910i.
The file is only unpacked, so you will need to go to the Application Menu of your phone, and select Applications -> Install and select Blackberry.
When the software runs, select Instant Email. You will now see the Blackberry icon flashing. Press the OFF button on the software to stop the Blackberry from trying to connect to GPRS.
Now open your Control Panel, select the Connections tab, and in here select Internet Accounts. Highlight BWC Blackberry.Net and select Edit, then Advanced and then rename the Address to blackberry.net
Turn your phone off and then back on. Hopefully now you should connect to the Blackberry server (Blackberry logo shouldn’t be flashing).
Go back into the Blackberry software and select Blackberry -> Register Now. This should tell the blackberry webserver your PIN and IMEI number.
Now on the internet with your computer visit http://mobileemail.vodafone.net/ and setup a new account.
If possible get your mail provider to Forward emails to the vodafone email address, instead of accessing it via POP3.
You should now have Blackberry working on your phone.
Points to note
You need Blackberry enabled on your account
You need a certain firmware version CXC16204x R2A17
This “should” work for other operators, but check what the APN needs to be to talk to Blackberry.
For more instructions on setting up an Enterprise Blackberry connect, read this post on HowardForums
Update – 23rd August 2005
The latest version of the software 2.54.4 works with CDA162005/3 R5A02
You can download it from here:
Update – 24th January 2006
Looks like this no longer works on Vodafone UK. PINs seem to be blocked for the P910’s 🙁
Update – 26th July 2006
Actually have this working again (for some months). If you have an Enterprise server, you’ll get around the PIN blocking. Vodafone have also decided not to support this software at all and it looks like they won’t support it for the M600i and the P990i.