Earlier versions of this application can be found here: http://code.msdn.microsoft.com/spwakeup
This is a ground-up rewrite of the application, focused on making it easier to use while improving performance.
In this new version, the searchdepth.conf file is no longer needed. Additionally, the sites.conf file is now optional. Performance has increased by about 30% compared to the last release.
If you are running your MOSS or WSS site on a single server, you can just run spwakeup.exe without any configuration files or run time options. It will search through the Site Collections hosted on http://localhost and find every site up to 3 levels deep.
If you need to wake up more than one Site, list them in a file called sites.conf located in the same folder as spwakeup.exe.
For complete instructions, run spwakeup.exe -help