This is awesome!
I've been thinking about making an app like this for some time now. Just yesterday I was thinking, "why haven't someone already done this?" and SMACK! Here it is!
I've been using it throughout the day now. I'm on vacation so I'm a bit lazier than usual... That means, I've spent a lot of time watching movies. So I made a project "Movies" and put WorkCoach to check "vlc" (vlc.exe), but when I watch movies I'm not active. So after a few minutes it'll start counting the time as Idle. It would be great if projects could have an option to count idle time as project time. Like the Movies project could have a checkbox that I click, and as long as VLC is the active window it'll count the time towards that - wether not I'm active or idle.
The Projects tab seems a little unnecessary, it could be merged with Rules. Because now I have to create a project in Projects, then go to Rules, select that project (because it's not default selected depending on what's selected in Projects) and set everything from there. I'd rather just have the add/modify/remove buttons right under the Projects list in the Rules tab. Or the Modify button in Projects could bring up a Rules window for that specific project so the Rules tab can be removed.
It would be nice to be able to reset the timer. So I know how I spend my time each day. And being able to export that data somehow, or view graphs of it.
Keep up the good work!