Forgetting a Computer from wi-fi sync on iPhone

A few weeks ago, I was visiting a friend, and they wanted some of the photos from my phone. So I synced up my phone to share only the photos, nothing else. Ever since then, in wifi sync on my phone, it has to where I can sync with that computer. I only wanted that as a one time thing. I never authorized my phone to the itunes store on that computer. Just synced. Is there any way I can remove that computer from wifi sync on my phone?

Thanks!