It can take weeks for search engines to index your blog. It's publishing posts, not pages frequently that attracts search engine attention.
The process we use for verifying free hosted WordPress.com blogs with search engines is found here > http://en.support.wordpress.com/webmaster-tools/
Note: Even if you do not verify the blog the content will be indexed by search engines so don't feel panicky about this please.
WordPress.com provides the search engines with site maps. We bloggers do nothing. http://en.support.wordpress.com/sitemaps/
For more information on search engine discover-ability and indexing read > http://onecoolsitebloggingtips.com/2010/01/21/omg-i-cant-find-my-blog-on-google/