Automatic (Interval) Partitioning is a feature of Oracle v11 http://download.oracle.com/docs/cd/B28359_01/server.111/b32024/partition.htm#CACHFHHF (click on it to see more details). This means that Oracle will create new table partition automatically. However I don't see any references in the Space Manager User Guide.
The process for Partitioning the table is not as automatic as his explanation/question above. You will have to determine how many partitions will be needed before using the Partitioning Wizard. BTW, there is a ppt document at the Space Management Community that walks through the process (with screenshots) for Partitioning a table: