[COLUG] Unmounting /var on debian?

[Linux User]

I have a debian 4.0 box with two disks using lvm2 and ext3.  The /var  
partition is too small.  I increased the logical volume containing / 
var without any trouble.  The problem is that I can't umount /var even  
after booting in single user mode.  I don't see anything open with  
lsof, yet umount reports device busy.  Unless I can umount /var I  
can't adjust the filesystem to take advantage of the larger logical  
volume.  The in place filesystem adjustment didn't work.

Any suggestions?