Brookville can be tough on a good day. I've fished there in teh winter a couple times and had mixed results (but I've fished in warmer weather and had mixed results too so take it with a grain of salt).
Normally, the stream has some decent hold over tourt, but I'm not sure how many are there now. Summer of 2009, they were doing some work on the dam and the stream got very low and very warm (close to 80 degrees) for about 2-3 weeks. It killed off a lot of the trout and there was some broohaha between some of the local residents and Central Indiana Trout Unlimited over some proposed stream regulation changes. Rumor is that what the warm water didn't kill, some of the fishermen from the town decided it was in their best interest to keep and eat every trout they caught.
I've heard the stream is rebounding and Indiana did a good job of stockig it this spring. This summer there were more normal flows and water temps so I would imagine there are still some trout in the stream.
I didn't get a chance to fish it this spring / summer but a couple guys I know siad they did pretty good there a few times over the year which is about normal.
If you go, midges (18-22 or smaller if you can see to tie them on), sow bugs, and BWO's have always worked well for me there.
Ceck the water gauge on the website you mentioned. If it's over about 3.8' the current is pretty swift. If it's over 4' it's really not safe to wade, especially in cold weather. There are some ledges and holes in the stream and if you can't see the bottom, don't go in that area. In the summer, not as big of a deal because even the deep holes aren't that deep and if you go in, it's easy enough to sit on the shore and dry off. In witner, it can be an entirely different matter getting back to your car wet and freezing.
If you get up there, I'd like to hear the report on how you did.