747b0392__5_1___Postgres_OnLine_Journal__Microsoft_SQL_Server_2008
[Feature] Job Scheduling Agent controllable from DB Manager client, for running batch sql and shell jobs - no additional charge (not CronTab) [MySQL 5.1] Yes - though appears can only use it for MySQL sql calls. [PostgreSQL 8.4] Yes - PgAgent and can run postgresql sql as well as batch scripts. Administrated via PgAdmin III. [Microsoft SQL Server 2008] 
Yes - SQL Agent (not for Express), administer via Management Studio. Can do sql, sql maintainence plans, batch scripts, and SSIS work flows. Its still the best. Has wizard for setting up maintenance plans.
Cross Compare of PostgreSQL 8.4, SQL Server 2008, MySQL 5.1 - Postgres OnLine Journal
Microsoft SQL Server 2008