Are you absolutely sure that it deleted your mac partition?
If you used the bootcamp utility then it should not have done that unless something really weird is going on with your computer.
Just a question, did you install the bootcamp drivers off the osx install cd that came with your macbook pro after installing windows?
That should allow the windows installation to read apple formatted drives, as well as install the bootcamp system tray, which will let you select your default boot drive.
If windows has become the default (which from memory from when I installed windows on my macbook pro became the case), then at the moment holding down option will not work, and neither will trying to boot off the install CD to fix your mac, as it is also formatted for mac.
Those bootcamp drivers on the install disk are important if you are going to run windows on your mac without any big problems.
If you have already done this, then maybe something odd has happened during the install.
Another possibility could be that you could have by mistake formatted over your osx installation while installing windows?
During the step that looks like this:
http://www.iclarified.com/images/tutorials/2672/10878/10878.jpg
could you have selected the wrong partition?
Hopefully someone will be able to help you out further on these forums.