There is no quick and dirty method. The easiest way involves re-installing.
It sounds complicated but it really isn't. I am working from memory because
I am not in Ubuntu now and because they have changed the wording with Lucid
and it has been a long time since I installed 9.10.

1. If you already have partitioned your drive skip this step. Boot the Live
CD because you cannot work from a mounted file system. Go to System,
Administration, Partition Editor. In the Partition Editor, choose the drive,
shrink your main partition, leaving enough space for your OS to continue to
work. Create a file system in the free space. Format it. Apply. Depending on
your set up you made need to create a couple of partitions in the available
space. You would do this if you have Windows as well as Linux. Generally you
need 2 partitions for Linux and one for whatever else you might want. If you
have Windows keep it where it is, just resize the drive smaller and make
sure the Linux partitions are after Windows.

2. Copy your home partition to one of the two partitions. You can drag and
drop your user name to the partition using Nautilus. It is worthwhile
backing it up to an external drive or DVDs just in case.

Note: if your HD space is limited, you may have to copy things from your
home folder to removable media before you begin to free up space.

Re-install Ubuntu where it was previously, but this time choose manual set
up. I am not sure of the exact wording these days, but it is usually the
last choice in the list. When you do a manual installation you get full
control. There will be both a graphical display of bars at the top with the
drive letters and a text display below that. I use the bars. Right click on
the partition where you want the root file system. Edit the partition.
Choose to use it. Then choose to format. Use ext3 or 4 and choose the mount
point as /.

Next do the same for the partition that you copied home files to, but do NOT
format. Choose to use it and the file format but you do not check the format
box. Set the mount point as /home. This is very important.

When you are done click Next to move on the the next phase. Use the same
user name and password. It will review your changes before it actually
begins to install. Read them carefully. If it says that you are formatting
home go back and do it again. If it is to your liking proceed. It should
format / but not /home.

When done re-boot.

An alternative method is not to re-install but to follow step one and try
to change /home to another location. You can do this in a couple of ways. It
is easier without using the GUI. One way would be to create second user
account in System, Administration, Users and Groups and locate it on the
drive where you want it. Then copy the contents (everything in your user
account, but not the name itself) including the hidden files (if you don't
know how to do this, go to View in the Nautilus menu) from your old user
account to the new one. The disadvantage is that you will have to use a
different user name. You can try to change your user account information
with a utility such as Ubuntu Tweak as well but this does not always work.

I suggested the re-installation method because it is fool proof and may be
less work in the end.

The best way is not to use the GUI. These instructions are quite good and it
includes graphics on the partitioning part described above.

http://www.psychocats.net/ubuntu/separatehome
or
www.trainsignaltraining.com/.../

Don't let the terminal scare you. Most of the terminal part can be done by
copy and paste.

Remember that all is not lost if things don't work provided you back up
before you try anything radical and this is radical.