It's really unattractive. Your text boxes look like buttons, probably due to the dropping of a hard border, the centred label, and the use of the unconventional yellow colour. This is a situation that's only made worse by the fact that the actual "Sleep On It" button looks identical to the text boxes, except for its background colour. Why would you make two widgets with entirely different uses look the same?
The entire site feels cramped. The layout of the actual entry form is frankly bizarre. Why would you wedge a check box in between two text boxes?
There's more, but I'm too lazy to keep going... take this back to the lab.
The concept is good although it needs more perfection.
Right now it appears to be a subset of what several reminder apps (e.g. my Outlook) can already do. Actually what I do in these scenarios is stick a post-it note on my screen.
The competitive advantage of your solution is obviously how functionality is streamlined for the sleep-on-it scenario.
Using your service is too much of a hassle at this point to replace my usual solutions (Outlook, post-it note, ...). Mastering the use case is the key difficulty in this exercise.
Think about how people already solve this problem and figure out how your product can make it better.
GUI improvements have already been mentioned, but if you are serious about it, think about mobile applications or at least a mobile web site, other means of notification (twitter?), multiple reminders (until the decision is solved), etc.
The entire site feels cramped. The layout of the actual entry form is frankly bizarre. Why would you wedge a check box in between two text boxes?
There's more, but I'm too lazy to keep going... take this back to the lab.