scheduling of index rebuild , analyze , etc...

Hi All

       I am fairly newbie to Postgresql and need to have the following done.

   

       ---- There have been a lot of data loads onto one of the databases and has resulted in some of the day to day queries to become very slow.

       I would like to perhaps Analyze the tables in this database as well as maybe rebuild the indexes (not sure on whether this is the right thing to do exactly)

     
       Can someone please assist me on how to do this and whether / how this can perhaps be scheduled to be done every so often.

        The database is postgresql 8.3

Regards
Machiel