I use this Simple Tagging system and it works with 2.2 from all my testing. And it does have a cloud that if you click shows all the posts from that tag.
See VistaDB Blog for an example. I am running 2.2.1 and the cloud on on the far right from the main blog page. It works great for me.
I use Simple Tagging for my tagging on my blog. I like it a lot, very simple to use, and you can create a tagging cloud on your site as well.
You can look at my blog for VistaDB for an example of how it works here
