I often share niche research tips, tricks and tools here at 5 Star. You can find a compilation of the best in the
stickies over here. I hadn't yet looked at any Twitter tools for niche hunting, so was happy to see that Ann Smarty over at Search Engine Journal did the work for me.
See: Track Hot Trends With Twitter Tools. Ann covers
Tweet Meme, and
TwittUrly a Digg style meme.
I like
Twit Scoop (below) because it's interesting to watch the tag cloud refresh in real-time as different topics get hot. Just doing that I got some great domain name ideas for a new site I'm going to build. PLUS when the affiliate tag went hot and I chased it, I found some great blog topics and new blogs to follow!
BONUS! BONUS!

Happy niche twitting, I mean hunting!