Hattrick Buddy-works wonders and is free. HAM-no idea and think it costs money. Hattrick Forum on Big Soccer-Free downloads into your head. Any others that I'm missing?
Buddy is what I use. Works very good. I don't believe it works on a Mac though. If you look in the Community-->Programs section of Hattrick it lists all the assistants and I believe there is one for the Mac. If you're needing it.