How to unlock a table after client dies during a transaction?

Hi,

My client application dies during a transaction ( insert into a table ).
Next time when connect to psql again and try to operate on the same table,
it's trapped in a deadlock scenario.  Is there any way to unlock the table?

And another problem is that if psql exit unexpectedly during a client
application during which a new table is created, the transaction is
rolled back, but a table with the same name can not be created anymore.
How to solve this problem?

Thanks a lot

Zhou