BootCamp dilemma

So to make the long story short, I accidentally formatted the Mac OS partition to Windows' NTFS file system and now cannot reinstall Mac OS because Disk Utility refuses to convert the partition back to Mac.

Initially, I used Boot Camp Assistant to split the hard drive into two. Next WinXP installation failed; so I ran the WinXP Recovery Console. After this, I can only see ONE partition when WinXP asked me to choose which partition to install it. And I end up being unable to start up with any OS.

What can I do to format the drive back to Mac file system?

Many thanks.

How are you trying to convert the partition back to the Mac file system?

You should be booting the machine with your original Leopard install DVD 1. Then use Disk Utility from Utilities at the top menu to erase the drive. Make sure both partitions are removed and the disk erased. After that you should be able to format the entire drive back to HFS+ and install OS X.

Regards.