If you have two Gmail accounts, you can use Google Talk to post notes to Gmail. First, set "Save chat history" in both Gmail accounts. Start Google Talk and sign in with your main account, add your "alter ego" as a friend and send an invitation. Sign out. Sign in with your "alter ego" account and accept the invitation. Sign out. From now on, every time you sign in with your main account, you will see that your "alter ego" is offline. It doesn't matter. When you want to post some note to have it available anytime/anywhere when you are online, just click your "alter ego" name and send it. Google Talk will respond with message - "alter ego" is offline and can't receive messages right now, but your message will be saved in chat history. Go to your Gmail account and check it. :-)
This also works with PortableGaim from USB drive, if you have it configured to connect to the Google Talk service. Isn't that great?