how does your /etc/fstab look like?
yout should have created three additional lines like this (untested, and i'm not sure if they are complete):
/dev/sdb1 /mountpoint1 ext3 defaults 0 0
the first argument (/dev/sdb1) is the name of the disppartition
the second argument (/mountpoint1) is the name of the directory where you want to mount this partition
the third argument (ext3) is the filesystemtype
for the rest of the argument i recomend a look at 'man fstab'