Web photo gallery, under the automate, is what I would use.

But, you know, I never updated to CS, so I'm only guessing that CS has web photo gallery still.

I actually keep an old copy of photoshop, 5.5, on my machine because I like the ease of using it's web photo gallery to do this kind of thing - later versions were a bit picky about where you put the output.

But, you can easily use a batch - just open a sample image from your folder, make an action that produces a final file at the size you want, then start a batch, use that action (if its the last action you made it will be the one batch assumes you want to use), point it at your folder, and hit the button.

Web photo gallery is safer because that batch WILL resize the actual images in the folder, while web photo gallery will make new smaller images and put them in a new folder, keeping your source images safe.

Altho you could make an action that saves it's results in a new folder easily enough...