I just published the first draft of a GreaseMonkey script for Twitter. I tweet frequently http://twitter.com/hising and sometimes I do it via the web (using Firefox) and there are some things I have come to be really annoyed about, first that the web do not automagically link hashtags to their search.So the first thing I did was to add this functionality. Next is to add extra functionality for following and grabbing status about tweeters in your list.
FrontEndBook.com Twitter Enhancer GreaseMonkey script on UserScripts
Interesting script, I love it.