I love the official Twitter Search Widget, but is there any way to remove the “Join the conversation” link at the bottom?
You mean like this? This link is temporary by the way, I'm not bothering to upload it to a permanent server.
If you're still around (this is an old question!) let me know and I'll hook you up proper. Just reply to this and it will send me an e-mail.
I can't find any way to remove the text, but you might want to try Tweetgrid which is highly customizable and can be integrated into just about any website scheme.
There's a few examples here of what can be achieved.