Is it possible to query the database for the values of an enumerated type in 8.3.3?

I have successfully created a user defined enumerated type using the
CREATE TYPE some_type_name AS ENUM command using Postgresql 8.3.3.

Is it possible to query the database (e.g. from psql or from the pgAdmin
III Query tool) for the enumerated values in the newly added user
defined type?

I did not find any direct documentation on this either in the manual or
on the web, but I may not know the correct search term(s) to use. Oracle
has a DESCRIBE command that does this type of thing for DB objects.
Perhaps the values need to be found indirectly by view some system
table?

Thank you!