Batch convert .tga to .dds?

Use Photoshop actions.

Could you elaborate please?

1. Create an Action to save from tga to the dds format of your choice. (Window->Action)

2. Create a Batch to run that Action on your desired files. (File->Automate->Batch).

Plenty of tutorials on the web for each of these steps (and in the Photoshop docs).

I recommend using DDS Converter 2 , a free and easy to use tool which can convert most commonly used image formats to .dds, using either the S3 or nVidia algorithms. Besides, its a lot faster than the nVidia plugin for Photoshop, especially if you work with textures bigger than 1024x1024. And yeah, it can work in batches.

When converting, simply select the nVidia algorithm and DXT5 for all your textures, including the normal maps. I tested it (in fact I use it myself) and it works fine with Sins.

I have tried DDS Converter 2.1, but it doesn't work for me.  No matter what I do, I can't get it to convert the textures.  I click on the files I need from within the program, but it does not add them to the conversion list, nor does it let me click the Convert button.

There is no conversion list as far as I know. I just select them and click "Convert". Try disabling the preview function and make sure your output folder is set (you can autoset it in the options).

The Convert button is still disabled.  I can select the files, but I can't click Convert.