You can download the remote app for you iPod touch, iPhone, or iPad. It's actually a much better remote. I just hope there isn't any configs to set up in settings to enable it. It's been a while since I set mine up.
Sorry, best I can recollect.
U should also hit up Craigslist for a used remote, those aren't the best for text entry, but it does what it's made for.
I had a simliar issue. I had Logitech Harmony remote that I was able to Pair with the Apple TV 2.
If you don't have one available, you can goto the Apple Store (or eBay) and buy a Apple Remote. The ones at the Apple Store we're $19 Canadian, and it has instructions of how to pair the remote with your Apple TV.
Overall, for the iPhone App to work with your AppleTV, it needs to be setup with a remote 1st, so you cannot just go staright to the iPhone app.