Notepad also come in handy when editing the .def files.
A small tip about .def files: These are easily made by copy-pasting an already existing vehicle .def file.
For example, if you are making a turreted tank, use a .def file from a already made turreted tank, and rename it into your new vehicle name (ie. if you use the .def file from the Sherman to create a M60A1, simply rename the .def file to M60A1) and then edit the file (change armor values, ammo onboard, speed etc with Notepad (or any similar word editor)).
If you decide to go with Milkshape 3D, here is a link to download the in-official plugins:
http://www.digitalmindsoft.eu/forums...-and-mod-tools
~Zeke.