First, warning. Do not use any disk repair utility, 99% of them will make your situation worse. There are only a handful that have any chance of fixing this, only one of them runs on Windows as far as I know.
Second, figure out if you need a backup. Since you don't already have a backup, in my opinion you don't value your data at all, therefore the easiest thing to do is to boot from the OS X DVD, repartition with 1 partition (in the Partition tab, change Current to 1 Partition), reinstall OS X, update it, Boot Camp Assistant to split your disk for Windows (or switch tactics and start using a VM which is much safer), install Windows. Done.
However, if for some inexplicable reason the data is important yet not important enough to already have a backup; you should take the opportunity to backup now. Go out and buy an external USB drive at least as big as your current hard drive. You can use Windows Backup and Restore, comes with Windows, to backup the Windows stuff if need be. If so, while maybe not strictly necessary (I've never used Backup and Restore) I would have Windows partition this new disk into two partitions: one for Windows Backup and Restore, one for copying data files from OS X. So you need to partition accordingly (i.e. roughly the same split as OS X and Windows are now), format both partitions as NTFS. Yes, if you copy OS X programs over to NTFS they may no longer work, so I would just copy over user data, like your home folder. Later you may have permissions problems, but that can be fixed after the fact, the most important thing is to have the files.
To actually fix the problem, is a.) risky and b.) non-trivial. So no matter what, you need a backup if you care about the data. So if you're not willing to go buy an external USB drive, it means you don't care about the data, and I don't have to spend time describing how to fix the problem. It will actually be quite tedious, the only tool I know that fixes this problem correctly, robustly, with the least difficulty and risk, is GPT fdisk. And it's a command line only tool. It's possible to fix this problem with Apple's tools on the OS X DVD, but that's a lot more difficult to describe because we'd have to use two different tools separately and more than once, to complete the fix, where gdisk can probably fix it in one whack. But again, if you won't make a backup, then the data isn't important. And you should just start from scratch. Easy as pie.
