Transaction progress

Hi,
is there any way to know a transaction progress state ? I'm executing queries from psql and I have a query running for 24 hours,
and I don't know when It will end, is there any way I could know it ?
if not, can I estimate the time from the explain result ? how ?
this is the explain result about the query I'm running:

Hash Join (cost=100347487.59..145240934.03 rows=26 width=60)
-> Index Scan using inars_rectificaciones_inx on inars_rectificaciones b2 (cost=0.00..37839140.62 rows=9546466 width=34)
-> Hash (cost=100347379.07..100347379.07 rows=43407 width=26)
-> Seq Scan on inars_nocontrib_perm1 (cost=100000000.00..100347379.07 rows=43407 width=26)

and this is the query:

update inars_nocontrib_perm1 set rectificada=TRUE,actividad=b2.actividad,presentacion=b2.presentacion,remuneracion=b2.remuneracion from inars_rectificaciones b2 where inars_nocontrib_perm1.cuil=b2.cuil and inars_nocontrib_perm1.cuit=b2.cuit and inars_nocontrib_perm1.ano=b2.ano and inars_nocontrib_perm1.mes=b2.mes;

Thank's in advance,

Pablo Yaggi