proper use of dump to backup a 5.3 box

[Steve]

This is a follow up to a question I posted not long ago about the best way 
to do a real, complete backup of a freebsd 5.3 box I'm using at home.  I 
was looking at several options to do a complete backup so I could recover 
my server (this is used at home for personal and development purposes) in 
case of a hard drive failure or whatever.  Originally I was leaning towards 
rsync'ing dumps to another older freebsd box I have at home but I just 
decided to put a 120 gig Western Digital USB drive on the server and backup 
to that instead of trying to do it over the network.

So I have this FAT32 120 gig drive connected to my P4 FreeBSD box that has 
a 40 gig drive and it works great and everything.  I created a 
/mnt/usbdrive directory for this drive and it's mounted successfully. In 
the /mnt/usbdrive directory I have two 
subdirectories:  /mnt/usbdrive/backups and /mnt/usbdrive/dumps.  I am using 
the .../backups directory to do a daily backup of selected directories from 
the P4 box and I want to put my dumps from the in the .../dumps 
directory.  I read the man page for dump but I'm still a little unsure of 
the proper way to use the command.  Can someone suggest the best way to 
actually execute the dump? (what flags and options, etc).  Sorry if this is 
n00bish I just want to do this right the first time.  I think this is the 
syntax I should use the first time:

# dump -0u -f /mnt/usbdrive/dumps /

Will this dump the entire file system to the usbdrive?  I want to do a dump 
once a month, what would the proper syntax be for doing an incremental dump?

Steve