I recently reinstalled OS X. My Bootcamp partition is still there with Windows 7 on it - can I tell Bootcamp about this partition so I can continue to use it?
Reinstalling OS X shouldn't affect the windows 7 partition at all since once installed, the windows 7 partition no longer relies on bootcamp (all bootcamp does is put a lot of drivers and what not onto the partition). You should be able to boot up the bootcamp partition as usual.
Note: if you can't boot up windows 7 something went wrong, and that would require more details.