Dig around and you can find several mainstream information providers who are twittering, although they are usually just sending their RSS feeds to Twitter via Twitterfeed rather than being actively involved in the community. Run a Twitter search on the BBC, Timesonline and the FT.
UKeiG is on Twitter at http://twitter.com/ukeig.It is mainly a Twitterfeed of the Yahoo! Pipes combined UKeiG RSS feeds supplemented by comments and updates. Some of you may prefer to view the feeds via this route. Comments and chit chat are welcome.