When using iPad, with Safari or some other application, once I find an interesting blog with its RSS feed, how can I add it to my google reader feeds?
The easiest route is to add a bookmarklet. See this link for details as well as the necessary Javascript you need to use.
Google reader is being decommissioned at the end of June. Ironically, a google search can point you to many other RSS sync services to replace google reader with.