One more tip. Make the title of your App as long as you can. Use up all 255 characters that Apple gives you. I'm pretty sure they have more weight then the keywords. An approach that I might take with my next release is using different keywords than what's in the title of my app to get more "keyword" coverage. This would give me about 355 characters of SEO juice in the App store. 255 characters for title + 100 characters for keywords = 355 chars.
I also experimented with iAds for the first time. Extremely easy to implement and setup. Early stats show that you need a sh*% load of impressions and click throughs to make any money. You might be better off advertising your other apps then using iAd.