Find Replace <em>copy</em>

I am merging data from a csv. Some of the text boxes are for descriptions. In some of these descriptions are html tags like <em> and <b>. I am not familiar with scripting at all... But, is there a way to find <em> and </em> and replace anything in between them to italic, and remove the tags? Please help... need to apply this on Monday.

thanks in advance.

CS3 on OS X