Download it, get the source for your openssh, untar/gz it, enter the openssh-3.1p1 dir that emerges and issue the command:
patch -p1 < /the/downloadet/openssh-3.1p1-chroot.patch
Make sure, its the openssh-3.1p1 version you use it on, since theres allready a 3.3p1 version, but this patch was orriginaly made to 3.1p1.
Then just use your regular:
./configure --with-chroot && make && make install
Restart your sshd, and you can now use chrooted $HOME via ssh.