a pretty common question, try looking at this thread.
http://www.linuxquestions.org/questi...7652#post67652
to make the partition usable tho, you'll want to use fdisk to change the partition type to linux standard or whatever fdisk calls it (type 83 i think) and then format it:
mke2fs -j /dev/hda1
this will make an ext3 journaling file system, omit the -j to just make a normal ext2 system. then just add relevant entries to /etc/fstab
