Have you seen the Wordle website ?
Create word specific images with specific words of just use a url and wordle will generate one for you, you can then customize it to suit. Bit fiddly to save but I found the easiest way was to open the image in new window size the window full screen and do a screen grab. Open in Photoshop crop or paint out boarders, I then made a selection inverted it to select only the text and saved to a transparent background. You can then use these on your website or blog posts.