In Reply To:
Based on what loxly said, she wants to insert SUB1 before description. She did not wrote "replace", but wrote "insert". I suppose she has descriptions already, and she doesn't want to delete them.
I don't remember how the Yahoo plugin works, so your answer may be still right.
Adrian got it right, I used the word insert because I didn't consider it replacing blanks. I would like to do what webmaster33 describes, but it isn't a big deal, I don't have that many categories that already have descriptions, and the ones that do could use editing anyway (this site is 3 years old). So for the categories that have descriptions I am editing them to use the SUB1 and moving the description to the meta tags.
Here's another related question, can I insert the contents of a field into the meta tags for the categories, something like:
<%Full_Name%> at <%sitename%>
in the meta description for instance?