I came across Wordle through another blog the author describes them as "Word clouds are fantastic and often quite beautiful ways of presenting information"
This could be useful way to present a large amount of text in a pictorial way. You could also use them to collate and store text.
However for a dyslexic learner they may not be that easy to understand.
To generate word clouds from text you can use http://www.wordle.net/create – it’s free and fun. If you want to save your word cloud to use in a presentation or document, just do a screen print and then edit it down to the size you want in Paint or any other simple graphics package.