Is it possible to search within a PDF document using Kindle for iPad? I am trying to use the Kindle iPad app as a storage base for all of my PDFs.  But I'm disappointed that I can't seem to find a way to search the text within a PDF using the Kindle iPad App.  Am I missing something?  Seems like a critical, missing feature.

Note that it is possible to search within a book on both iBooks and Kindle. This question is specifically about PDF. It is also possible to open these files in Acrobat Reader or OSX Preview, and the text is searchable within those applications.
No.

As of version 4.5 of the kindle app for IOS in pdf searching is  not available.

As of version 1.10.7 of the kindle app for OS X in pdf searching is available.