It should work just like your first example—provided your search url syntax is correct.
Code:
<a href="http://ax.search.itunes.apple.com/WebObjects/MZSearch.woa/wa/search?media=all&term=Random+House%2C+McCarthy">Link Text</a>
Link Text
I don't have iTunes so it won't let me (or anybody else who doesn't have an iTunes account) even see the results of such a search, so....