Dynamically discovering field names in PLPGSQL queries

Is there a way to discover the names of the fields in a record from a SELECT
statement in PLPGSQL?

For example:

SELECT INTO REC * FROM mytable;

Is there a mechanism to determine what the "*" expanded to? or does a
programmer always have to know the layout of the table apriori?

Wade Oberpriller                 http://www.storagetek.com
Software Development             Phone: (763) 424-1538
StorageTek: MRDC                        (800) 328-9108 ext. 1538
wade_oberpriller@storagetek.com  Fax:   (763) 391-1095