groovycatmedia:
According to your signature, you are running Snow Leopard (as am I) - in which case iCloud does not sync with your Mac at all. However, it can be accessed (apart from photos, gee thanks, Apple!) via a web browser.
But wherever you're creating your notes, if they're not getting from iPhone to iCloud, the solution may be quite simple:
You're probably creating your notes in an (email) account that doesn't sync with iCloud.
"What?"
Rather than me explaining, do this: on your iDevices, go to Settings > Notes > Default Account.
Chances are this will be set to On My iPhone (or similar) or to the name of an email account that isn't iCloud.
Set this to iCloud.
Er... that's it.
Now when you create a new note on your iDevice, it should automatically sync to iCloud.
Apparently iCloud on the web only displays notes created in the iCloud account on your iDevice.
For JackJohnsonsea and others who don't get syncing in either direction, the solution is to follow the steps above and then on your iDevice make sure you are displaying all notes:
In Notes, tap Accounts (top left).
Now tap All Notes.
Presto! All your notes will be displayed.
FWIW I think the log out/log in/reset/delete/recreate workarounds are just resetting the default display of all notes on the iDevice.
Needless to say it is a sadly all-too-typical Apple design flaw that the default library page of Notes does not tell the user which set of notes are being displayed or that others may be available in other accounts.
I hope this helps somebody.