Just a few things:
1. Doesn't make much sense to have a link to home page on the home page - WakeMyself is a link.
2. It'd be nice to make step 1, 2 and 3 boxes to be same height, as well as vertically align the controls in those boxes, so they are on one visual line. Currently it's a bit too "jumpy" (look at big text field, then look a bit up to see time entry, then down on "wake myself" button).
3. I'd be nice to have "sign in" as either popup or just sliding area on the frontpage, without having to navigate to a separate page.
4. "remember me" does not align with actual checkbox (osx, latest chrome)
5. No error messages seems to be displayed when logging in with non-existing account.
6. When signing up, on "Fill out profile" page there seems to be a bit too much of the whitespace between the actual title ("Fiil out profile") and controls panel.
7. "Sign up" text on button on "Fill out profile" is a bit misleading - have I already signed up or not? If yes, than it should read something else. If no, then it should reflect that as well.
8. Is service US-only? It probably should say that straight away, so people from other countries don't waste their time signing up. (Actually you do already, but only on the front page - needs to be on sign up page as well I guess).
9. "Sign out" should probably mention user name somewhere, that's just a common UI convention.
That's just a cursory glance.
Thanks.