(clug-talk) Whoopsie using 'dd' cmd, need advice

I need to make a note not to try anything that requires thinking when I'm 
coming down with a cold...

I was trying to get LILO onto the MBR of the first disk (I have two) in my 
system by copying the MBR from the second disk.  I won't go into the gory 
details why, but suffice it to say it could've waited until I'd had some sleep. 
 :P

Here's what I did:

dd if=/dev/hdc of=/dev/hda bs=512 count=1

Looking at it now, I'm laughing because it's so wrong, but I was tired and 
wanted results... well, I got some.  :P

My question:  to what extent have I eradicated data on the first disk?  Is 
there a way to get the partition tables back?

Thank you in advance,
Curtis