It's a lot cheaper (free) to just read through the Hydraulic Reference Manual and figure out the interface using the User Manual. Having read the HRM, I think I got a better understanding of the program than I ever could've on a 3 day or 1 week course.
It is somewhat pricey, but HEC offers training courses. It fills with Corps folk first. People I know who were able to get funded absolutely loved the course. As far as other courses make sure you get a reference for the specific trainer. (Everyone wants to teach)
I did what francesca mentioned and then took an advanced course. It helped because I understood all of the open hydraulics and courant number stuff, but balancing energy flows through bridges is a trial and error process that was easier in a class setting the first time.
