Ext4/Ext3 question

[Steven Vollom]

When I installed the Jaunty Rc release, I labored over the thought of using 
ext4, remembering all the prior warnings.  Nonetheless, I installed using the 
ext4 file system believing the problems would surely be resolved in the Rc.

The file systems that currently hold my data in partitions are ext3.  Is it 
possible to change them to ext4 while data is still in them?  If so, what is 
the procedure?  Thanks!

Steven