Hi David, I don't think you can edit the keywords shown within your store, but you can turn them off if you want. Here is how to turn keywords off.
Click your Manage Store Link
Then Click on Look and Design
Then Click Store Layout and Content
Then find the box that states "Keywords" and uncheck the box if you want the keywords off.
I have my list of keywords off and just show the search box for customers to use within my store..
Hope that is helpful.
Happy Thanksgiving.. Sher