Right. After a frustrating evening of trying to deal with all sorts of issues relating to Second Life, mine own Hosts and Twitter itself, it seems that the TwitterBox version 0.1 is now ready for release, and I have placed an open copy in my freebie box - available in the usual place.
I have put up a permanent Twitter-related page from which you should always be able to get the latest version and/or news. It also contains a link to the TwitterBox Basic, an LSL-only client that can only post, not receive tweets.
I may write further on the matter but for now I must retire.