Apple have added an extra attribute to applications on iTunes store - keywords.
Be careful though. It appears you can only update your keywords ONCE per application update - so make sure you choose the right ones the first time around - otherwise you'll have to go through the painful approvals process to get it corrected.
The keywords should help with searching for your application within the store. Fingers crossed.
--- EDIT ---
You can also only have up to 100 characters for the keywords. Don't get caught out! If you submit with more than 100, it tells you too late - you'll have to resubmit your app to fix it.