how to use pg_resetxlog

Howdy

Running PostgreSQL 7.2.1 on RedHat Linux

This past weekend, the RAID array took a hit and crashed
the database. I get a few errors like:

[snip]
DEBUG: invalid secondary checkpoint record
FATAL 2: unable to locate a valid checkpoint record
DEBUG: proc_exit(2)
DEBUG: shmem_exit(2)
DEBUG: exit(2)
DEBUG: reaping dead processes
DEBUG: startup process (pid 23543) exited with exit code 2
DEBUG: aborting startup due to startup process failure
[/snip]

I'm reading around and I see a bit of information about
using pg_resetxlog, but I don't know much about it.

1) How do you use pg_resetxlog?
2) Am I at risk of losing all of my data
if I use this?
3) Some info at groups.google.com suggest that I will
have to initdb - I figured that would be good anyway, but
how does pg_resetxlog play into this?

TIA!

-X