> > Both "buses" and "busses" are acceptable
plurals of "bus". At least according to
dictionary.com, anyway.
>
> "Busses" is the second spelling listed in
some dictionaries and not listed at all in other
dictionaries. Generally one should not trust
the second spelling or pronunciation variation
listed in dictionaries. Lexicographers tend to
be too permissive and eager to decrease the
literacy rate by making language errors correct
as quickly as they occur.

All I know is; thanks to this thread, I'll never
mispell the word "buses" again.