With the release of 4.1 on the horizon, and initiatives such as Krush days, recent call for help with documentation, and the perennial need for localisation it is very useful for end users to be able to easily get their hands on up-to-date builds of KDE4, preferably without having to wait for their chosen distro to provide packages. As was the case with the run up to KDE4.0, KDE4Daily VM aims to provide such a service.
For the uninitiated, KDE4Daily aims to accomplish this goal using Qemu virtualisation technology (although with KDE4Daily 4.0, people kindly stepped up to provide a VirtualBox/ VMWare equivalent). A self-contained Qemu image with a Kubuntu 8.04 base and a comprehensive set of a self-compiled KDE4 modules (all at r810996, initially) is provided, along with an updater system inside the VM itself. The updater downloads and installs binary updates provided by me to the full set of modules; these tend to be roughly 20-50MB each (although they will occasionally be larger), take a few minutes to apply, and will hopefully be pushed out daily - hence the name ;). "Bridge" updates will hopefully condense a week or so's worth of updates into one more compact version, so you can update at your own pace without being hit with a massive bandwidth bill :)
Because Qemu is distro-agnostic, you do not need to worry about distros or libraries or dependencies or suchlike; in fact, you can even test out KDE 4 while running Windows! The downside is that eye-candy such as KWin's new Composite-based effects will not be testable as Qemu does not support hardware graphics acceleration, and everything will generally feel a lot more sluggish than is the case with a native install.
KDE4Daily comes with its own backtrace-generation system so hopefully devs can be assured of having useful backtraces in any crash bugs you file, courtesy of DrKonqui. Do note that this system is currently rather slow and resource-intensive, although there are plans to improve it during the run of KDE4Daily 4.1. If you do somehow manage to crash a KDE app, please be patient while the valuable backtrace is created!
An extensive FAQ is provided at the KDE4Daily homepage, above; please feel free to ask any further questions in the Dot comments section. Also, note that KDE4Daily has not yet had any real testers apart from myself, so please be prepared for "teething trouble" such as botched upgrades and bandwidth issues! Enjoy, and remember that the more people test, the better KDE 4.1 will be. It's not all work, though; if you just want to try out recent deliciousness such as the KRunner and Marble, then that's fine, too!