I've been using a variation of this search script for a while so I thought I'd update it with some customization settings nailed on and post it (there's a simple snippet version of it here). The thing is: I often want my iTunes search results to go directly to a playlist so I can get right to work on them there, usually tag editing. Without some automation this is typically a multi-stage grind comprised of searching, selecting track results, making new playlist, naming new playlist, locating and selecting the tracks again when new playlist gets focus (stab!), putting tracks into playlist by any one of various means, and then forgetting why I was searching for these tracks in the first place. (Related memory-loss issue: Name New Playlist From Selection.)
Search Results to Playlist puts a floating window over iTunes that provides the ability to search iTunes and copy the track results to a designated Results Playlist.
It can search the entire library, the selected playlist, or any of the categories (Music, Movies, Books, etc) for text in All, Name, Artist, Album, or Composer tags and then copy the results to a playlist. The script will create this Results Playlist if necessary. If the playlist already exists then the track results can replace its current contents or may be appended to it.