As of 2008-03-09, versiontracker was still showing Insomnia ver 1.3.2 as current with a download link for same. Actually ver 1.3.3 is current, be sure you download this from the website or thru the check for updates feature. Ver 1.3.3 works with OSX 10.5.2 on my macbook pro.

Regarding overheating with the lid closed, according to apple tech support, macbooks and macbook pro's have thermal protection. But it's a sensible idea to turn off the built-in screen before running with the lid closed, obviously.

If you use Insomnia, please consider making a reasonable donation. Development of utilities like this should be encouraged -- and rewarded.