yep
i used to do it.
Buy the rights to the domain you want, and then setup forwarding to the ntlworld address. You can use framed forwarding if you don't want the homepage.ntlworld.com/etc part to be shown, or standard forwarding if that doesn't matter.
hth
MB
EDIT: bear in mind thought that the ntl space does not support any server side technologies; you might be better off paying 99p per month for an iweb package
MB