pgcryto strangeness...

Just started using the pgcrypt 0.4.2 (very cool stuff) and am having
some strange errors (not so cool). Can someone make sense of the SQL
below? I'm not 100% sure what's going on or not going on...

host=# SELECT DIGEST('asdf', 'md5') FROM users_shadow;
digest
------------------------------------------------
\221.\310\003\262\316I\344\245A\006\215IZ\265p
(1 row)

host=# SELECT DIGEST(password, 'md5') FROM users_shadow;
ERROR: Function 'digest(varchar, unknown)' does not exist
Unable to identify a function that satisfies the given argument types
You may need to add explicit typecasts
host=# SELECT DIGEST(CAST(password AS bytea), CAST('md5' AS TEXT)) FROM users_shadow;
ERROR: Cannot cast type 'varchar' to 'bytea'

Any ideas as to how I can do this? -sc

--
Sean Chittenden