Hung backends

Hi,

I'm new to PostgreSQL and have been tasked with determining the cause of
hung processes on FreeBSD after the frontend app dies. Eventually we run out
of connections when hung processes = MAXBACKENDS.

ps -cl -U postgres returns:

UID PID PPID CPU PRI NI VSZ RSS WCHAN STAT TT TIME COMMAND
500 1395 1 0 2 0 4040 2380 select Ss ?? 0:01.17 postgres
500 2255 1395 0 2 0 4384 2984 sbwait I ?? 0:00.01 postgres
500 2256 1395 0 2 0 4384 2984 sbwait I ?? 0:00.01 postgres
500 2257 1395 0 2 0 4384 2984 sbwait I ?? 0:00.01 postgres
500 2258 1395 0 2 0 4384 2984 sbwait I ?? 0:00.01 postgres
500 2259 1395 0 2 0 4384 2984 sbwait I ?? 0:00.01 postgres
...

The java frontend I'm using to test this scenario makes multiple connections
and crashes(unhandled exception) before disconnecting. This appears to leave
one "postgres" proccess for each connection. Can anyone point me in the
right direction?
SELECT version(); -> PostgreSQL 7.0.2 on i386-unknown-freebsdelf4.0

Thanks for any advice.
Peter Schmidt