Image WaterMarker 1.1 lets you add watermark text over any .jpg, .gif or .bmp image. What this does is let you brand your images, so people are less inclined to right click and copy them from your site.

The software lets you choose the font, size and transparency of the watermark text, and (with the latest update) also rotate and choose the position of the watermarked text. It is very easy to use.