Here is a list of common questions:
No: Not now but maybe someone will port it. Meanwhile you can run Kdenlive on any of the many free Linux distributions. Give it a try, you may like it so much that the question of running it on Windows becomes moot.
Yes: download a CD-boot only GNU/Linux distribution including Kdenlive 0.7.
Apply the "volume" audio effect.
A line will show up in the waveform of the clip.
If you double click any point on that line, a new keyframe will be added in which you can adjust the level.
If you then double-click on the keyframe (it appears as a square on the line) you can then manually type in the desired level or shift the keyframe to an exact time.
Kdenlive 0.7 does not have a video crossfade/dissolve transition by default.
You can either use a "composite" transition or a "luma" transition to achieve a crossfade.
For a luma transition, just use one that "looks right". With composite, you can get a real crossfade/dissolve by applying a composite transition, then add a keyframe to the end of the transition and set its opacity to 0.
For some more discussion of the composite transition, please see mantis issue 261 .
Add the image to the project, then double click on the image in the project tree.
This will show a dialog with an option saying "Transparent background". Just check that box, and then when the image is inserted in the timeline, an alpha transparency transition will be added automatically.
Kdenlive is constantly looking for contributors:
Check our contributor guide for more information:
Kdenlive is free software in all meanings of the expression.
You can find a camcorder database at: http://kdenlive.org/video-editor 
If your camcorder is not listed and you have tried it with Kdenlive, please enter it in the database so that other users know if it works correctly.
Excellent: FFMPEG project is the most advanced project providing video and audio codecs.
We plan to release a stable version of Kdenlive every three months.
There is probably more than 1000 registered users on our forum. As it is Free software, we don't know exactly the size of the community. Recently, we registered on Google Analytics and will publish detailed statistics.
YouTube has introduced HD.
Use Kdenlive 0.7.1 as H.264 export is better. Refer to this document:
These export profiles has been added to Kdenlive recently:
YouTube 1290x720 2000k
YouTube 640x480 800k
It is recommended to create a project with the same resolution as the target export resolution.