Ref. Url: https://www.google.com/support/googleanalytics/bin/answer.py?answer=91502&hl=en_US

What do the different Website Profile tracking status messages mean?  

After you install the Google Analytics Tracking Code on your site, you will not see data appearing in your reports until at least 24 hours after installing the code. However, you can always check the status of your installation in the Website Profile section of the Analytics Settings window, under the column “Status.” The following tracking status messages can appear for your profile:
Waiting for Data
The tracking code has been detected on the home page of your website, and Google Analytics is aggregating the data to populate into your reports.
Tracking Unknown or Not Verified
The tracking code has not been detected on the homepage of your website, so please verify that you    have installed the code correctly.
Receiving Data
The tracking code is working properly and data is being populated into your reports