This is some tech workaround way. I don’t know whether this is worth the effort but with so many social networking sites around nowadays, you can try this. Click on the time below your tweet. That particular tweet of yours will open in a new page. This is the page you would want to appear in search results. So you can submit it to various social bookmarking sites like Digg, Reddit, Stumbleupon etc. I have tried one for my Picasa vs Flickr article and as you can see here it works fine. Only drawback is that the user has to click across two extra pages which could be frustrating. So do it wisely for your tweet!