Apple :: I Messed Up My Bootcamp Partition And Now It Won't Delete

I wanted to install vista. I did the normal bootcamp procedure but forgot and extracted candy bar at the same time the partition was being created.after the partition was created and the message appeared telling me to insert my windows cd appeared, my mac froze. I held down the power button and forced shut it down. I switched it on again and windows setup started. Everything went on fine and i booted in windows fine. However , when i wanted to enter my os x partition, it would start and go up to the part where the rotating circle would appear. It continued rotating for a long time and then restarted my mac. I tried again several times and it did this. I then booted my mac from the os x install dvd and selected install os x on the windows partition. Setup failed. I launch disk utility and verify and repair disk partition (There was no problem when i did disk check). I restarted my mac and everything booted fine. I now have a new partition labeled "mac os x". I launched bootcamp manager and tried to restore my disk and get the error: "The startup disk cannot be partitioned or restored to a single partition: The startup disk must be formatted as a single mac os extended (journaled) volume or already partitoned by Bootcamp Assistant for installing Windows".

How do i format it in this format? Do i have to use the setup disk again or do i use disk utility?