Was searching for a way to do ordering within CONNECT BY clauses in Oracle PL/SQL, and came across this great article on all sorts of aspects of Hierarchical data support within Oracle 9i.
Querying Hierarchies: Top-of-the-Line Support
Particularly interesting facts include the ability to ORDER SIBLING BY to order within a Hierarchical query, and using SYS_CONNECT_BY_PATH to display an output of the tree in delimiter separated list.
Good reading!