increasing size of a partition

[dave]

Hello,
    I've got a 5.4-release box that is in need of some partition maintence.
It's using raid1 procedure1 from Mr. Ralf S. Engelschall's site:
http://people.freebsd.org/~rse/mirror/
I haven't been able to get procedure2 to boot, i keep getting an error on
boot that the kernel is not found. This is worrysome because the two drives
are not identical in size, they're close, and usually unless the partitions
are filling up i don't worry about it. Lately /var has been filling up, when
this box was installed space requirements were not estimated to be like they
are now. I've got a single slice covering the entire drive and four
partitions, /, /usr, /var, and /home which is last on the drive because it
takes up the most space. Now i need to increase the size of /var probably
taking space away from /home, does anyone have a procedure for doing this
keeping in mind that geom mirror raid1 is going on?
Thanks.
Dave.