How do I create a database if I can't connect to it?

Hello,

For a short description, I'll just show the sequence of commands I'm trying
to execute:

paolo(at)box> initdb -D /usr/local/pgsql/data/
paolo(at)box> postgres -D /usr/local/pgsql/data -i -p 5435
paolo(at)box> createdb foo -p 5435
createdb: could not connect to database foo: FATAL: database "foo" does not
exist

And

"postgres -D /usr/local/pgsql/data -i -p 5435"'s output:

/*
LOG: database system was shut down at 2007-07-27 11:25:27 BRT
LOG: checkpoint record is at 0/42C4B4
LOG: redo record is at 0/42C4B4; undo record is at 0/0; shutdown TRUE
LOG: next transaction ID: 0/593; next OID: 10820
LOG: next MultiXactId: 1; next MultiXactOffset: 0
LOG: database system is ready
FATAL: database "foo" does not exist
*/

Now, am I doing something terribly wrong/noobish, or Postgres is freaking
out because I want to create a database that does not exist?

Thanks in advance,
~Paolo