Good luck. Have you used the Android store? I love Android, but the store could use a lot of work. I haven't used the apple store, so I can't compare, but they Android market is a mess.
I haven't; but Google's great strength is searching large datasets for useful results. I can't imagine them not figuring out how to make the Android store work well if they set their minds to it.
This may become a problem with the Android market too -- in fact, I already see it happening sometimes, when searching for particularly common application words.
I hope that Google/Android system implements some better ranking algorithm in a way that it manages to find which words are actually relevant to an application. Not sure how that'd be done, though.
My original comment might be a bit misleading. Its actually ok to use tagged relation in a market with a large barrier to entry because then its prohibitively expensive to create "spam" entries. This works for Netflix. The problem with the iTunes store here is the low barrier of entry for people to create crappy applications and get them listed.