The new Synergy version, 4.5.2, is now out. Synergy is a lightweight, highly-customizable iTunes controller. The 4.0 series is a brand new line of development especially for Mac OS X 10.6 Snow Leopard.
This is a maintenance release which has been tested against the latest iTunes (version 10.1.2) and which has some internal code clean-ups.
Note that the 4.0 series will only run on Snow Leopard. (Version 3.4.1, the last release in the stable series will run on all versions of Mac OS X from 10.2.8 upwards.) A full changelog appears here.
For many users this release will be a free upgrade: see this blog post to find out whether you qualify. If you got Synergy through the MacHeist Giving Tree bundle see the MacHeist FAQ.
The Synergy product pages were recently completely revamped for 4.0, so be sure to check them out.
You can download the new release from the download page and purchase a license using this page.