If you can't find the e-mail that was sent, the following should help.
Visit http://wordpress.com/my-stats and select the blog on the right drop-down menu you'd like. If you want stats on the blog already selected, select another and then go back to it.
Notice the address of that page, something like http://wordpress.com/#!/my-stats/?unit=1&blog=14358310
Take that blog= number (14358310 in this case) and replace the XXXXX in the URL below:
This works when you have multiple blogs under your account. If not, it's kinda screwy, but you can find it out by going to:
http://flarmenians.wordpress.com/wp-admin/index.php?page=stats and click on one of the small "Summaries" links above right of the bar chart. The blog ID will be in that page's URL.
There may be a super easy way to find this that I don't know about.