I'm not SURE, but, hda should be your main drive, and hdb should be your slave.. Not positive though...
However, I do know the answer to your second question
Install lilo for a boot loader. In order to boot windows from that, just put the following at the bottom of /etc/lilo.conf
Then run /sbin/lilo
Thats assuming windows is on hda. If its on hdb, then change it to /dev/hdb.