Simone Carletti is reporting (in Italian) that SiteStats is available to PRO users. I can confirm that I see a new Site Stats item in the left sidebar of the Analyze tab in FeedBurner. I was able to go to Standard Stats and enable site tracking. Since I already have FeedFlare, I don't need to add additional code. I'll report back what happens. FYI, I'm not a PRO user of FeedBurner. Really!
http://www.simonecarletti.com/blog/2007/01/feedburner_site_stats.php
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an user on my blog confirmed that stats are available to all accounts.
When I activated them I have been redirected to TotalStats PRO page (I don't know why) thus I thought they were only for PRO users. :)
-- Simone