Search your tags
TagsAhoy lets you search all your tags, across different sites, from one location.
Just sign up (it's free), enter your account information for the sites where you use tags, and you're done--you can search all your tags from one place. Takes a few minutes.
Now with widgets! By default, your tags are private and searchable only by you. Once you've signed up you can choose to add a tag search widget to your blog or website, and make them public.