This tool converts many formats (*.bmp, *.png, *.tga, etc.) into DirectDraw Surface (DDS) files. This is most useful for textures and such. It also works for other games as well.
The included file is an MSI file, so you need Microsoft Windows Installer to work properly. For more information on that please visit this link.
"The primary goal of this program is to enable the conversion in batch and in control of several types of image files into DDS format, be them saved in BMP, JPG, PNG, PSD and TGA. However, other kinds of conversion are also possible."