Watershed Tools:

1. ESRI Hydro Data Model

2. GIS Hydro 2005 Preconference Seminar Website

3. Hydrological Modeling Toolbar

On the left hand side where there is what looks like a table of contents, navigate to Samples, then Spatial Analyst, then Hydrologic Modeling. At the bottom of the page in Hydrologic Modeling is a link to download the suite of .dll files and other things one needs for the HM toolbar to work, as well as instructions on how to use it.