Updating FreeBSD 8.0 to 8.1 (methods and policy)

Question

I have 8.0-RELEASE-p4 + few ports installed. I wonder wheather I should update to 8.1.

1. How long is 8.0 supported?
2. How to update the system? I couldn't find anything about it in handbook.

SOLUTION (based on gvkv answer): I take the liberty of describing all steps I've done at the end:

# STEP 1: Revert to GENERIC kernel
cd /tmp 
wget -r ftp://ftp.freebsd.org/pub/FreeBSD/releases/i386/8.0-RELEASE/kernels/
cd pub/FreeBSD/releases/i386/8.0-RELEASE/kernels/
sha256 generic.* install.sh | diff - CHECKSUM.SHA256
./install.sh GENERIC
nextboot -k GENERIC
# STEP 2: Upgrade - part 1
freebsd-update upgrade -r 8.1-RELEASE # Ignore kernel warning. Fix configuration
freebsd-update install
shutdown -r now
# STEP 3: Upgrade - part 2
nextboot -k GENERIC
freebsd-update install
shutdown -r now
# STEP 4: Upgrade - part 3
rm -rfv /usr/obj
portmaster -Raf # Rebuilds all packages. If you don't use portmaster use other tool or do it manually
cd /usr/src
make buildkernel KERNCONF=CUSTOM # Rebuild kernel
make installkernel KERNCONF=CUSTOM # Install kernel
shutdown -r now

Answer 1

1. The 8.0-RELEASE branch will be supported until November 20, 2010. If you want stay on the the 8 branch (RELENG-8) you will have least until July 31, 2012; if there are any update releases in that branch then you will have until at least two years past the release date of the point release See the links given by Stefan Lasiewski.
2. Updating is as easy as following the instructions.

Answer 2

1. According to http://security.freebsd.org/#sup, FreeBSD 8.0 is supported until November 30, 2010.
2. We're still trying to figure out the "Best way" to do this. There's more then one way to do it, and the FreeBSD docs are too ambiguous. Also keep in mind that "Updating FreeBSD" is considered a separate topic from "Updating the most software (e.g. ports and packages) on your system".

The page at http://www.freebsd.org/doc/handbook/updating-freebsdupdate.html talks about updating FreeBSD.

Answer 3

You also might want to see how to rebuild the base system when updating. That is how I do it...