A tag cloud or word cloud is one more way to put navigation on web site. There are different ways to create tag cloud.  For example collocate cloud can be found at scottishcorpus.ac.uk website . From Wikipedia “a collocate cloud provides a more focused view of a document or corpus. Instead of summarizing an entire document, the collocate cloud examines the usage of a particular word. The resulting cloud contains the words which are often used in conjunction with the search word.” 
The post in the blog  describes second generation of tag clouds and the trend for the future. Looks like tag clouds will stay here and will get more complicated, useful, powerful, dynamic and with more different features.
Having your own script to generate tag cloud provides more flexibility and power in creating tag cloud and automating posting/updating it on the web. Thus I created some perl script, online demo and service for tag cloud. In the future it will be updated with more features like different colors, automatic updates and other features. You can find it at Tag Cloud Generator Please fill free to provide any feedback or suggest features to add.
 Collocate cloud