idle in transaction process

Hi All

I am using postgres-8.4.0 on a cluster setup with slony-2.0.4 being used for
replication.
Recently , I saw a "idle in transaction" postgres process as below.

postgres 13052 14742 0 May13 ? 00:00:00 postgres: slon abc 172.16.1.1(49017)
idle in transaction
I wonder what could have lead to that hung postgres process . I googled
about it a lot and they say that it could be
because of abrupt netwotk issue between slony and postgres . But in my case
slon was connected
to its local postgres database. So, network wont be an issue in this case .
What else could be the reason for
this hung process ? What should I do to come over this kind of issue in
future. I think this hung process would have
taken locks on various tables. I wonder if killing the "idle in transaction"
process would cause the locks on the tables
to be released or not. Can anyone please help me on that.

Thanks in Advance .

Tamanna