How do I delete an online directory on a 3G T-Mobile My Touch?

I was messing around with my phone today, and I found an option in the contacts that you could transfer over online directories (facebook, twitter, flickr, etc). I tried it out and signed into facebook and my phone is now linked up with my facebook contacts. The problem is, it's using too much memory from my phone. I don't want my online directory to be linked up anymore, but can't seem to find any option to sign out of it via online directory. Does anyone know how to do this? Please help!