Like the idea of this Twitter/Flickr mash-up site Portwiture. It takes words from recent tweets and pulls in Flickr images based on those keywords.
The idea is very interesting and shows why tags are so important. But, not sure the images reflect the words that well. You can specify the types of tweet with a range of filters – recency etc and also by Flickr account. Developing these filters could make for some interesting results.