"slow lock" log in addition to log_min_duration_statement ?

I have a cluster with log_min_duration_statement set to log slow 
queries. Presently what I'm tracking down is almost certainly a lock 
problem.  Is there any analog of log_min_duration_statement for locks?  
If there is a lock on a certain critical tables for more than a few 
hundredths of a second I want to know.

Similarly in pg_stat_activity, is there a way to get the parameters to 
the current_query?  I see the placeholders (e.g. $1, $2) but not the data.

This is with PostgreSQL 8.3.4
Thanks!