VTFTool by Jed (aka Wunderboy) is a GUI-based replacement for several SDK command line tools for handling VTF texture files. Like VTF2TGA, it can take a VTF file or folder of files, and convert them back into TGA format for editing. You can also export all the MIP images for a texture, plus export a TXT file which contains the config settings for re-compiling the TGA back into VTF format. It can also convert TGA files into VTF format and create a basic VMT shader file for your texture.
It is not a fully integrated creation tool, but designed more as a simple GUI replacement for the default SDK tools.
- VTFTool - the official website.