multi-user machine OS X backup solutions?

[Martin Portman]

hi,    a similar question to before.

i have three macs: a cube and 2 ibooks.  on the same network.  none of
them are heavily used.  they are used daily, but not a great deal of
data is generated.  i'm looking for a backup system that will work for
all of them.

cube    = 80gb, about 30gb of music,              OSX 10.1
ibook 1 = 30gb, small amount of personal stuff,   OSX 10.2
ibook 2 = 60gb, ditto,                            OSX 10.3

its really just the /User bits i need to backup.  all else i can
reinstall (there's not much extra in there).

things i'm looking for are one (the same) solution for all 3 machines,
and once or twice a month scheduled backup.  i could upgrade all to
10.3 if really needed.

what are the possible solutions?  and what are the pros and cons of each?

thanks in advance,
martin.