You can upgrade by phoning Customer Services on 0800 052 2000.
I think you can also upgrade online, via the ntlworld.com homepage.
But....
In case you didn't know, it isn't actually necessary to subscribe to the special XBox package to be able to use XBox Live.
[well...it is technically against the Terms & Conditions to use XBoxLive via ntl without paying them their extra subscription.....but it depends on how you read the Terms, & besides, they won't be able to find out if you use XBL without the ntl XBox service...see this post for my opinion on this:
http://www.cableforum.co.uk/board/sh...841#post215841 ]
All the ntl XBox service gives you is 2 IP addresses (1 for your PC, & 1 for your XBox).
Instead of using the ntl XBox service, you can:
1) Use a direct connection, & simply swap leads from PC to XBox (or vice versa), remembering to power cycle the modem each time. See here:
http://www.cableforum.co.uk/board/showthread.php?t=715
2) Use Internet Connection Sharing (ICS). This will let you use the PC & XBox online at the same time, although it requires the PC to be turned on to use the XBox online. See here:
http://www.xbox.com/en-gb/live/start...pc/default.htm
3) Use a router. This is IMO the best option. The modem plugs into the router's "WAN Port" & the PC(s) & XBox plug into the router's "LAN Ports". The router shares the connection, enabling you to use more than one thing online at the same time. You can get a very good (& cheap) router from Amazon & other places: The
Linksys BEFSR41 - it costs just over 30 quid, & is well worth it. See here:
http://www.xbox.com/en-gb/live/start...er/default.htm
If you subscribe to the 2 IP service, you will be, in my opinion, wasting your money. I believe there is also a set-up fee too, which makes it even more of a rip-off.
I have been using XBox Live via my ntl broadband connection since the "Test Drive" started in December 2002 - and I have only ever used a router to connect my XBox, never the extra ntl broadband & console service. Most people I know on XBoxLive with ntl use either a router, or ICS, or a direct connection - not the ntl console service.