Glad to know you like Heartbeat. The version that is up right now on
http://heartbeat.highgroove.com/ is still very much working (we use it
to monitor all our sites)!
The sad part is, we do have another version -- an improved version of
the application with even more features, but have been so busy with
client work that we haven't been able to launch it.
I'll try to put up the code to the railsday version on our public repo
soon, and ping you about it.
Thanks for the message!