Tutorial: Unity + Parttools Setup, Model Import and Export into KSP.
Channel: Tiberion
Date: 07/11/2013

A quick video detailing how to setup Unity with the KSP Part tools scripts, import a model and texture and then export it into .mu format so that it will load into KSP.

For more information:

KSP Addon Devleopment Forum: http://forum.kerbalspaceprogram.com/forums/37-Add-on-Development
Download Unity: http://unity3d.com/unity/download/archive (Download 4.2.2 - versions 4.3+ have issues with Part Tools)
Download Part Tools: https://www.dropbox.com/s/i6m6erpfhv1xb11/PartTools%20020.zip
Part Tools Info: http://forum.kerbalspaceprogram.com/threads/34013
Part Config Tutorial: http://forum.kerbalspaceprogram.com/threads/25013-Compilation-of-modding-information-links-for-0-19-20-21-22-Last-update-11th-Nov?p=642248&viewfull=1#post642248
Modding Info Compilation: http://forum.kerbalspaceprogram.com/threads/25013

If  you have any issues, you can always create a topic on the forum.
Feel free to send me a PM on the KSP Forums - username: Tiberion