find overlapping address ranges

This is more of a SQL question than a pgsql question. I know this
should not be hard, I just can't wrap my mind around it. Thanks...

So I have a table with street names and address ranges. Some of the
address ranges overlap for the same street ranges, and I need to write
a report on those rows. In other words, I want to do something similar
to this:

SELECT gid, street, fromleft, toleft, fromright, toright
FROm cityplus WHERE
HAS_OVERLAPPING_ADDRESS_RANGE_FOR_SAME_STREETNAME()
ORDER BY street

Does this require a subselect? Stored procedure? Neither? Can I use a
pgsql line geometric type to check for overlap? This data is in Postgis
as well, so I have those methods at my disposal as well.

Table "cityplus"
Column | Type | Modifiers
------------+-------------------+-----------
gid | integer |
street | character varying |
fromleft | integer |
toleft | integer |
fromright | integer |
toright | integer |
fnode_ | integer |
tnode_ | integer |
lpoly_ | integer |
rpoly_ | integer |
length | double precision |
netcurr_ | integer |
netcurr_id | integer |
l_low | integer |
l_high | integer |
r_low | integer |
r_high | integer |
str | character varying |
dgn | character varying |
q | character varying |
stanno | character varying |
code | integer |
the_geom | geometry |
Indexes: cityplus_addnum_index,
cityplus_geom_index,
cityplus_gid_index,
cityplus_oid_index
Check constraints: "$1" (srid(the_geom) = -1)
"$2" ((geometrytype(the_geom) =
'MULTILINESTRING'::text) OR (
the_geom IS NULL))

Alex Rice
Mindlube Software
http://mindlube.com/