Emergency questions for new bie

Hi,

I'm an Oracle DBA, lately I  began a project work on  PostgreSQL 6.5.3
for Red Hat Linux 6.0.

Every thing is fine, except:

1.How can I enable PG run as 'no-fsync' mode to improve performance? How
can I check PG is in 'fsync' mode or not?

2. We have a table contain a column which use 'timestamp' data type.
'cause we need both date and time in this column, and don't want to
break it into two columns with 'date' and 'time' data type(if so, we may
have to change thousands of lines code, it origrinally works on Oracle).
But when I tried to create an index on this 'timestamp' column, I got
this error and creating failed: 'Cannot find a default operator class
for type 1296.'

I use this SQL command to create index: create index ind_name on
tab_name(col_name);

Can't I create index on 'timestamp' column? Right now since there's no
index on this column, our app runs very very slow!

THanks a lot!

Jack