http://www.wunderboy.org/3d_games/utils/sourcetools.php
Includes handy VTF to/from TGA converter.
Update: Using the app that is included with the development kit worked for me. I haven't really tested this. All I use is the handier VTF shell extension.
Now all I need is a handy TGA to/from BMP converter.
Edit:
http://www.irfanview.com/
And the man in the crowd said, "Let custom textures be prevalent!".


Corny, yes, stupid, yes.

Update:
Click the link in my signature and download Laztor v3 to get handy omini-sized pictures of all of the pieces.
They have black backgrounds and are good for part-spawning systems.

Please place them in the same folders I have placed them, this is to prevent multiple downloads.

In addition:
-You need a res file if your map is not included with mod updates!
-Place the textures in SteamApps/Email/Half-Life 2/HL2/Materials as well as the SourceForts directory.

Credit to me is not necessary, but it took me awhile to gather them poses.