More suggestions

In the Hop Bitterness tool, it would be nice to choose pellet/leaf/plug for each addition, since I use some of both. Also, more than three additions. Maybe just make one field, with the option of adding another addition indefinitely.
Also, the "boil volume" is a bit misleading. Is that boil volume at first pitching, or 15m before, or what? (Most of us boil for a hot break before pitching, no?)Changing it to say boil volume at first pitching would eliminate confusion and give better numbers.

Yeasty,
  I agree it would be good to add the hop type to the bitterness tool.

  For more than three additions, you might want to consider just creating a recipe - since it allows as many additions as you like!  The limiting factor on the hops tool is screen space.  It is intended for quick addition calculations.  If you want to do a complex addition schedule, a recipe offers a better format.

  The boil volume is the pre-boil volume.

Cheers!
Brad

So, why when you change the boil time does it change the IBU's?

Yeasty,
  There is a pretty simple answer: the longer you boil hops, the more alpha oil gets extracted from the little glands in the hops.  Its the boiling process that extracts these oils - longer boil=more oils.  The alpha oils provide the majority of the bitterness you perceive when you drink the beer.  The various IBU formulas all take boil time into account for this reason.

  Therefore longer boils result in more oil, more bitterness, and higher IBU. 

Cheers!
Brad

http://www.beersmith.com/forum/index.php?topic=1098.0;topicseen