On my website I have a selection of wishcard texts.
People should be able to select one text. A pop up will then show a beautiful card (image/template will be provided) with the selected text on it (you should write the code that takes the text from the website and puts it on the "whishcard"). People can than type their names on the card and post the personalized card on the someone's facebook wall.
Extra info can be provided.
Small budget for easy task.